New Operational Combat Series (OCS)



2.2 New Sequence of Play

Weather determination

Note that the player turn order is fixed in the scenario and does not change; there are no double moves.

First player turn

Reinforcement phase – reinforcements appear, supplies are received, rebuilds and replacements are taken, all as in normal OCS

Air operations phase – all phasing player air operations, refit, missions, resolution

Movement phase – ready artillery units, fuel formations and HQs, change modes, movement and overruns, construction

Bombardment phase – phasing player’s artillery and naval barrages only, paying their supply costs

Combat phase – phasing player conducts desired combats in any order, paying their supply costs.  Defending player may conduct defensive artillery support and pay supplies for full defense strength.

Enemy reaction phase – reserve mode non-phasing units may move with overruns possible, no combat or barrage phases.

Exploitation phase – phasing exploit and reserve mode units may move with overruns possible, no barrage phase.  Second combat phase for phasing player reserve and exploiting units only.

Supply phase – breakout option, then all phasing units check trace supply or eat off the map, suffer attrition if they cannot be supplied.  Units back in supply remove OOS markers, newly OOS units are marked OOS.

Recovery and clean up – All phasing DG units recover and non-phasing DG units recover from “Fire” DG, fuel markers flipped or removed, non-phasing trainbusting markers are removed and non-phasing interdiction and patrol air units are returned to their airfields inactive.

Second player turn (as the first, sides reversed)

Turn end, advance the turn marker

2.5 New sequence of play discussion

There are no double moves because the turn order is fixed by the scenario.

Air operations are consolidated into the air phase at the start of the turn instead of spread over every phase in a “just in time” fashion.  This is a deliberate downgrade in air-ground coordination to reflect the level of such cooperation in WW2, which was not yet 1970s-1980s style NATO “air-land battle”.

Bombardment is consolidated into a single bombardment phase after movement and before combat by the phasing player only, instead of spread into 4 such phases for both phasing and reacting players.  Defensive artillery fire is allowed only for a combat DRM without using the Barrage table.

Enemy Reaction phase is moved to after combat and before exploitation instead of before combat.  Therefore it can be used to plug holes but not to reinforce threatened hexes before combat resolution.  Defensive barrages are limited to combat DRMs as described above.

The supply phase is moved to the end of the player turn instead of its beginning, so a surrounded formation has its full turn to move or fight its way back into supply before needing to break out or suffering attrition.

Another major change is to DG recovery.  Units DGed by bombardment table results now recover at the end of either player’s turn, so fire DG goes away at the end of the player-turn in which it was inflicted.  DG caused by 2+ hex retreat in a combat result stays unti the end of that player’s next turn as in original OCS. 

All of these changes are meant to put more of the focus on prior planning and combat, less on timed “interrupts” and just in time interventions.  There are also fewer changes of control within the turn, bombardments need to be planned further ahead, and fire DG needs to be followed up quickly or it will dissipate.

3.2a Unit type additions

Armor (yellow), mechanized (red), and armored artillery units (artillery symbol inside armor symbol) are “hard” for density effect and retreat after combat purposes.  All other unit types are “soft.”  These new categories are used for certain Bombardment and Combat density effects.

In addition, mechanized red units with armor symbols e.g. Russian armor divisions or corps are considered 50% heavy AT and 50% light AT units for armor advantage purposes.  Other red units are 100% light AT units.  Both are “hard” units for density effects and retreat after combat effects.

4.3 Stacking changes

There are no changes to the 4.3 stacking rules, but a few new rule cases are needed for the revised ZOC rules and combat density effects.

Hexes with 1 combat step or less never create ZOCs.  2 steps or more in combat mode create ZOCs, as do 3 steps or more in movement mode.  Units in DG or strategic movement mode never have ZOCs.

Hexes containing 6+ soft steps suffer 2 columns shift right on the barrage table and -2 DRM attacking to LHS CRT results.  6+ non soft steps suffer 1 column right on the barrage table and get -1 DRM for attacker LHS results and +1 DRM for defender RHS results for density.  These are the only density effects.

4.5 ZOC changes

Hexes containing 2+ steps in combat mode project ZOCs, and 3+ steps in movement or reserve mode also project ZOCs.  Non-combat units, 1 step hexes, strategic movement mode, and DG units never project ZOCs.

ZOCs are “soft” for all units in Combat Mode.  They cost +1MP to enter or to leave for truck and track combat move units, but do not require moving combat mode units to stop.  Leg movement units in combat mode pay nothing extra to enter a ZOC, but do pay +1 MP to leave a ZOC.

ZOCs are “hard” for all units in Movement Mode, meaning they stop movement as soon as they are entered.  They cost leg units +1MP to enter or leave, and trucked or tracked units +2MP to enter or leave.  Units entering a ZOC in movement mode must halt or conduct an Overrun against at least one hex exerting the ZOC into their hex.  If after an overrun they are still in a EZOC hex, they must halt for that movement phase.

One hex minimum movements may be used to move from EZOC to EZOC in combat mode.  Units in Movement Mode can never move directly from one EZOC to another EZOC.

Units in Strategic Movement Mode may not enter an EZOC.

Friendly combat units negate EZOCs for purposes of tracing supply, supply path distance MP cost calculations, transport unit movement, and retreat after combat purposes.  They do not prevent extra MP costs for entering or leaving a ZOC for combat units or HQs.

All “hard” units may retreat through EZOC without extra step loss if and only if the hexes projecting the ZOC contain no Armor units (yellow or red).  Soft units always lose 1 extra step for retreating through an un-negated EZOC, and hard units do so if retreating through an unnegated EZOC projected by at least one enemy Armor unit. The extra loss is 1 step per stack for the full retreat, regardless of the number of EZOCs entered.

ZOCs and terrain – ZOCs do not extend across any impassible hexside.  ZOCs do not extend across unbridged major rivers, even for leg units or units in combat mode.  ZOCs do extend across major rivers at permanent bridges or temporary ones created by combat mode HQs or engineer units, or special bridge markers.

5.0 Mode changes

5.7 Units in Reserve Mode lose that mode if enemy units move adjacent to them; remove the Reserve Mode counter.  They do not defend at 1/2 strength.  A unit that starts its move phase adjacent to enemies may still enter Reserve mode provided it uses its 1/4 movement allowance allowed in that phase to break contact; it cannot be in reserve status adjacent to enemy units after completing that move.

Artillery units that barrage in their barrage phase “tap” and are unable to provide defensive artillery support until ready again.  Artillery units automatically ready at the start of their friendly movement phase.  No special mode is needed to conduct defensive artillery fire, just not being “tapped” in the enemy combat phase.

DG mode now has 2 forms, “Fire” DG recorded with small DG counters in Vassal or single DG markers face to face, and “Combat” DG recorded with large DG counters in Vassal or 2 stacked DG markers face to face.  Fire DG is placed by all bombardment table DG results.  Combat DG is placed only when a defending force retreats 2 or more hexes as the result of a CRT combat result, whether by overrun or in a combat phase.  The effects of DG are unchanged in both cases.  Fire DG is removed at the end of each player turn for units on both sides – remove 1 DG marker in each clean up phase.  Combat DG thus lasts until the end of the owning player’s next player turn.

No other changes.

6.0 Movement changes

Entering and leaving EZOCs now costs additional MPs – +1 MP per ZOC entered or left for combat mode non-leg units and leg units in Move mode, +2 MP per ZOC entered or left for wheeled or tracked units in Move mode.  Leg units in combat mode pay +1 MP to leave a ZOC but no extra cost to enter a ZOC.

Entering an air interdiction hex costs +1 MP for units in Move mode, and in addition any road in such a hex costs a minimum of 1 MP per hex.  This replaces the OCS 4.3 series rule on “trainbusting zones”.  Air interdiction affects the mission hex and all surrounding hexes in this manner.  In addition, Strategic mode units may not enter an air interdiction hex.  Air interdiction zones also increase the MP costs for transport units and supply throw distance MP calculations; see the air missions section for further  details.

Air transport missions now occur in the air operations phase, not the movement phase.  Ground units moved by air in the air operations phase are tapped to show they previously moved by air, and may move only 1/2 their MA in the normal movement phase.  They may change mode but may not enter Reserve or Strategic movement mode.  Supply points moved during the air operations phase may not be moved further by rail, truck or wagon in the movement phase, in accord with “no leapfrogging” rules.  They may be spent or “thrown” by direct draw and HQs.

No  other changes.

7.0 Reaction phase changes

The reaction phase now occurs after the phasing player’s combat phase and before his exploitation phase.  The reaction phase does not include any bombardment phase nor any combat phase, it is only movement and overruns within that movement.  Only Reserve Mode units may move in the Reaction phase, and they remove their Reserve Mode marker as soon as they do so, adopting the Mode under that counter.

Units that have enemy combat units move adjacent while in Reserve Mode now automatically lose their Reserve Mode marker.  They are not halve in combat if attacked, but they will be unable to react since they will no longer be in Reserve Mode at the start of the Reaction Phase.

Defensive artillery barrages in the reaction phase have been replaced by Defensive Artillery Fire during the combat phase.  This does not use the Bombardment table procedure, but instead gives a -1 DRM on the combat roll in return for 1T supply cost spent by at least 12 bombardment factors in range of any of the attacking units.  Units used for Defensive Artillery Fire at tapped and may not be used in further Defensive Fire that same combat phase.  All tapped artillery units untap at the start of their friendly movement phase.

8.0 Overrun changes

The MP cost of overruns remains 3 MP and ZOC or interdiction costs are never paid for overruns.  Units in movement mode that enter an EZOC pay +2 MP for that EZOC (+1 for leg units), and must either overrun (for 3 more MPs) or halt.

If a stack attempts an overrun and fails to clear the target hex of defenders, then its movement for that phase ends.  It may not try again or move elsewhere.

If an overrun attempt against a given hex fails, no additional overrun attempt can be made against that hex in the same phase.  Units displaced by a previous overrun may be attacked be overrun again, but not in the same hex as a previous overrun that phase.

Any Movement mode units in an over-running stack that end their overrun still in an enemy ZOC must end their movement.  Combat mode units may continue moving, remaining MA permitting.

Allowed terrain – overruns are allowed against any type of terrain except across a major river or into a mountain hex (this is deliberately less restrictive than the original – small forces in patches of swamp terrain e.g. did not hold up entire Panzer divisions for multiple days).  Full terrain effects on combat still apply normally to all overrun attempts, and they have the same supply costs as any other combat.

Note that all defenders forced to retreat 2 hexes or more are DGed and therefore lose their ZOCs; stacks reduced to 1 RE will likewise lose their ZOC, or 2 REs if in movement mode.  2+ hex retreat DG is the full “Combat” DG and lasts until the end of the owning player’s next turn.

Overun combats use the normal new ambush and surprise combat type procedures; attacker surprise it not any more likely than in ordinary combat phase attacks.

9.0 Combat changes

Besides the sequence of play and air operations, the most extensive changes of the new system are all to the combat procedure.  There is a new CRT with two sides, the left hand side containing the results suffered by the attackers determined by the absolute defense strength of the defending units, not the combat odds, and the right hand side containing the results suffered by the defenders determined by the combat odds.

This results in attacker expected losses varying with the defense density and prevents high final odds from “protecting” the attacking units from battle attrition.  The battle type surprise procedure is also changed – now folded into the same 2D6 combat roll – and combat DRMs are different than the original, with the effects of AR differences more limited than in original OCS.  Details of all these new procedures are given below.

The base column for the RHS of the CRT is determined by the combat odds after all modifiers to strength.  The base column for the LHS of the CRT is determined by the defense strength of the defenders only, after all modifiers to their strength.  DRMs and column shifts may occur to either side of the CRT as outlined below.


This new CRT is a core feature of the new OCS system.  It is based on considerable research and modeling of the determinants of actual battle outcomes in WW2 combats.  The new system is designed to reward proper tactics but also to keep the scale of combat effects within the range of variation actually seen for different drivers of WW2 battles.

For experienced OCS players, three major changes are important to understand about the new CRT.  One, defender expected losses begin to match attacker expected losses around the 2-1 odds column for open terrain fights, which is considerably sooner than on the original CRT.  Two, it is much less feasible to reduce attacker losses just by bringing higher odds to the combat; higher odds raise defender losses and retreats but do not lower attacker losses.  And three, it is much harder to substitute large AR differences for raw numbers than in RAW OCS; while higher AR units will fight much better than low AR ones, having a 4 point AR difference will not allow a 1 to 1 odds fight to go off as though it were a 5 to 1 odds fight.

Armor advantage and the AT system

New OCS still uses the combat factor multipliers for tank and mechanized unit types of the terrain effects chart as normal, and has a revised system for “capping” favorable attack factor multipliers similar to rule 9.4e of the series 4.3 rules.  This procedure is used to calculate an Armor Advantage which is either Attacker Armor Advantage, Defender Armor Advantage, or neither.

If every attacking tank or mechanized unit faces a reduction in its combat factor from the terrain effects chart (multiplier strictly less than 1.0x), then no Armor Advantage is calculated.  There is automatically No Armor Advantage in this case, and the full TEC multiplier is applied to each involved unit.  Thus any attack on a major city, for example, or with all units across a minor river, is automatically No Armor Advantage.

If at least one attacking tank or mechanized unit would earn a terrain multiplier of 1.0x or higher, then the armor advantage is calculated.  In all other terrain types, there is no armor advantage calculation performed and neither side has armor advantage.

If the calculation comes out as Defender Armor Advantage, then the maximum TEC multiplier for attacking armor and mechanized units is 1.0x, and in addition the battle resolution gets a -1  DRM on both sides of the table.

If the calculation comes out as No Armor Advantage, then the maximum TEC multiplier for attacking armor and mechanized units is 1.5x, and there is no armor DRM for this combat.

If the calculation comes out as Attacker Armor Advantage, then the full TEC multiplier for attacking tank and mechanized units is used (usually up to 2.0x for clear e.g.), and there is in addition a +1 DRM on the battle resolution on both sides of the table.

The armor advantage calculation depends on the Heavy AT Odds if either player has Heavy AT capable units present.  If neither has any Heavy AT capable units, then it depends on the Light AT Odds.  Light AT is never consulted for armor advantage unless neither side has Heavy AT.  The single Armor Advantage level arrived at this way governs the combat multiplier for all attacking yellow and red units.

Heavy AT effects are given to all yellow coded units and 1/2 to red coded units with tank symbols, and full to defender’s (only) anti tank, anti aircraft symbol units.  Light AT effect are given to all other red coded units.  This is the same as rule 9.4e except that only defenders may count their Anti tank and Anti aircraft symbol units, hedgehogs do not confer heavy AT capability, and red armor symbols units are only 1/2 heavy AT.

To be clear about the treatment of red units, those without armor symbols are 100% light AT.  Those with armor symbols count 50% of their strength as heavy AT and the remainder as light AT.

Total all heavy AT attacking strength in the combat and divide by all Heavy AT defense strength to arrive at the Heavy AT odds ratio, rounding normally.  If this ratio is 1-1 or less, then the Defenders have Armor Advantage for this combat.  If this ratio is 4-1 or higher, then the Attackers have Armor Advantage for this combat.  Otherwise, neither side has Armor Advantage for this combat.  The procedure for Light AT is the same, but is only used if one or both sides do have light AT strength but neither has any heavy AT strength.  Note that all attacking units, yellow or red, are affected by the resulting Armor Advantage level.

Example – and attacker has 5 yellow heavy AT strength from a German assault gun battalion, and the defender has 18 red light AT strength from an infantry symbol Russian motorized division.  The heavy AT odds are 5 to 0, greater than 4-1, so there is Attacker Armor Advantage.

Example – as in the previous, but the attackers also have a strength 3 light AT strength armored car battalion.  The attack is still Attacker Armor Advantage, and even the attacker red mechanized strength benefits from it.

Example – this time the attacker is a strength 18 red armor symbol Russian tank division, which provides 50% of its strength as heavy AT, and the defenders have yellow 5 German assault gun and red 3 armored car units.  The heavy AT odds are 9 to 5 which rounds to 2-1, and the armor status is no Armor Advantage.  In clear terrain the Russian tank division would get 1.5x  to 27 attack factors but would not earn any DRM for this combat.

9.5 Combat supply cost changes and defensive artillery fire – the supply cost for attackers is reduced to 1T per 2 attacking REs.  Defenders can spend 2T for full defense strength for 3+ REs, 1T for full defense strength for 1-2 REs.

Defenders may also elect to pay 1T for Defensive Artillery Fire if they have at least 12 ready artillery bombardment factors within range of at least one attacking hex, tapping the artillery units used to do so if they decide to use such support.  These supply costs can be paid out of existing stocks by marking units “low” or “exhausted”, but it will cost 1T per RE to restore those stocks from “low” or 2T per RE from “exhausted”, in the next friendly supply phase.

If the defender used Defensive Artillery Fire, there is a -1 DRM to the combat roll on both sides of the CRT.  This requires 12+ ready bombardment factors in range and 1T supply cost.

All modifications to combat strength for DG or lack of supply work just as in 4.3 OCS.

Terrain effects on combat and hedgehogs

Close terrain only gives 1 shift left on the right hand side of the CRT, it has no effect on the defensive fire (left hand) side of the CRT.  In addition, swamp / marsh terrain is only close terrain; its additional effects are given by the reduction in attack strength for attacking armor and mechanized units and their need for a road to attack into them.

Very Close and Extremely Close terrain both gives 1 shift left on both sides of the CRT.  Extremely Close terrain also confers a 1 shift left vs Bombardment table attacks, and gives the defender the ability to cancel R1 results on the CRT.  R2 and higher results must still be taken normally.

Level 2-3 hedgehog earns 1 shift left on both sides of the CRT.  Level 4 hedgehog earns 2 shifts left on both sides of the CRT.  These may be used along with terrain shifts, but the maximum hedgehog level in Very Close or Extremely Close terrain is level 2.  It is thus never possible to earn more than 2 shifts left for terrain and hedgehogs combined.

Extremely Close terrain or Level 4 hedgehog both give the defender the ability to ignore R1 retreat results.  R2 and larger retreat results must still be taken in full.  There are no Optional CRT results; step loss results must always be taken as step losses and retreat results as retreats.

Extremely Close terrain or level 2 hedgehog or better gives 1 shift left on bombardment table attacks.  These are not cumulative, and never more than 1 shift left is ever earned on the bombardment table for terrain and hedgehogs combined.

Combat Quality level changes – the defenders always use the highest available AR for any of their combat units in the defending hex.  The attackers must use the lowest AR among all attacking units unless they have Formation Integrity for this attack, in which case they may use the highest AR rating from any unit in that Formation, instead.  To have Formation Integrity, all surviving combat units of at least one Formation must be taking part in this attack, from one or more hexes.

Surprise determination changes

There is no separate die roll for surprise before the combat roll.  Instead, the combat roll uses 2 dice of different colors, one white and one red.  The white die controls Ambush – defender surprise – and the red die controls attacker Surprise, if and only if there is no Ambush.  If either obtains, it changes the battle outcome, not the odds column used to resolve the combat.  One 2D6 roll always fully resolves the combat.

Normally, the defenders achieve “Ambush” (defender surprise) if the white die for the combat roll is a “1”, and the attackers achieve “Surprise” (attacker surprise) if the defenders do not achieve Ambush and the red die is a “6”.

Defenders cannot achieve Ambush if all defending units are DG. Hedgehogs and overruns have no effect on ambush and surprise determinations.

If the defenders AR level for the battle is 2 or more above the AR level of the attackers, then defenders achieve Ambush on a white die “1-2” and attacker Surprise is impossible.  Note that 2+ higher AR but also DG defenders could make both forms of surprise impossible.

If the attackers AR level is 2 or more above the AR level of the defenders, then Ambush is impossible and the attackers achieve attackers’ Surprise on a red die “5-6” on the combat roll.

There is no DRM for the net AR level of the combat.  Instead the effects of AR differences are much more limited, as follows.

Attacker AR level 1 higher, +1 to RHS combat result only

Attacker AR level 2 higher, +1 to both sides combat result and attacker surprise on red 5-6.

Attacker AR level 3 higher, +2 to RHS, +1 to LHS combat result and attacker surprise on red 5-6.

Attacker AR level 4 or more higher, +2 to both sides combat results and attacker surprise on red 5-6.

Defender AR level 1 higher, -1 to LHS combat result only.

Defender AR level 2 higher, -1 to both sides combat results and defender Ambush on white 1-2.

Defender AR level 3 higher, -2 to LHS, -1 to RHS combat results and defender Ambush on white 1-2.

Defender AR level 4 or more higher, -2 to both sides combat results and defender Ambush on white 1-2.

There is no additional effect for a AR differential larger than +/- 4.

Notice that slightly higher AR only raises enemy losses, it doesn’t lower your own.  Substantial AR differences both raise enemy losses and lower your own, and substantially increases the likelihood of beneficial surprise, but will not outweigh very large differences in raw strength.

Ambush or attacker Surprise do not shift the outcome column.  Instead they change the final combat result.  Ambush reduces by 1 each the step losses and hexes of retreat required of the defender.  If the defender lost no steps on the original combat result, then the attacker step loss requirement is increased by 1 instead.  Attacker surprise increases the hexes of retreat required of the defenders by 1, and reduces attacker required step losses by 1.  If the attacker lost no steps on the original combat result, then the defender step loss requirement is increased by 1 instead.  If neither Ambush nor attacker Surprise occur, then apply the rolled CRT result normally.

Combat density DRMs

If any attacking hex contains 6+ “soft” REs, then the LHS combat result (only) gets a -2 DRM for attacker density.  If the former does not apply but any attacking hex contains 6+ REs, then the LHS combat result gets a -1 DRM for attacker density.  If the defending hex contains 6+ REs of any kind, then the RHS combat result gets a +1 DRM for defender density.

Assigning step losses

The first step loss either side takes in a combat is chosen by the losing player, but must match or exceed the AR rating they used for the combat.  If the combat involved yellow armor on both sides, each side that was not armor advantaged in that combat that has a step loss to fulfill must lose a step from a yellow armor unit (or red armor symbol division with yellow armor capability).  Second and later step losses in the same combat are chosen by the step-losing from among involved combat units, but may not take losses from artillery or HQ units if he has combat units present to take the loss instead.

Attacker retreats and defender retreats with terrain advantages

Attackers are never required to retreat as a result of combat.  This is a change and reflects the distance and time scales involved.  WW2 attackers essentially never retired multiple miles for days as a result of a repulse unless subject to a significant defender counterattack.

Defenders in extremely close terrain or in level 4 hedgehogs may ignore R1 one hex retreat results.  This includes CRT R2 results that were reduced to R1 by Ambush (defender surprise).  In all other cases, defenders must take all retreat results in full and may not reduce them by paying extra lost steps.  If defenders retreat 2 or more hexes, all surviving defending units are DGed.

Retreats, advances, and exploitation

If units are forced to retreat through EZOC as a result of combat, they are subject to additional step losses unless those EZOCs are neutralized by the presence of friendly units.  Note this is a change from 9.12e – EZOCs are now neutralized by the presence of friendly combat units for retreat step loss purposes.

Each retreating stack must lose 1 additional step for entering a non-neutralized EZOC.  (Exception: retreating yellow or red units only pay this extra step loss if at least one enemy yellow / Hard AT unit projects this EZOC, otherwise they may ignore this loss requirement).  This never exceeds 1 step per retreating stack per combat, regardless of the number of EZOCs entered.

Advances and exploitation are exactly as in 4.3 OCS.

9.11d Effects of step losses on combat strength

A unit with 3-4 step original strength that is -1 step loses 4 combat factors in combat mode and 2 combat factors in movement mode, on both attack and defense.  Any unit with half or less of its original steps remaining loses half its combat factors on attack or defense.  This replaces the 4.3 series rule that the first step loss reduces only attack strength.  In addition, 4 step  units that are on their last step apply both of these reductions, so e.g. a German 4 step infantry division in Combat mode has 20, 16, 10, and 6 combat strength as it loses steps.  In Move mode it has 10, 8, 5, and 3 respectively.

10.0 Barrage changes

Barrages are centralized into the air operations phase for air barrages and the single phasing player Bombardment phase after movement and before the main combat phase.  There are no other bombardment phases in the game turn, and air and artillery units never combine in the same barrage.  Naval fire support occurs in the bombardment phase along with artillery fire.

A new barrage table is used, with a reduced set of left and right shifts possible, new lower barrage supply costs, and streamlined results (no 1/2 results).  The main result is still DG for all units in the target hex, with “1” results causing a single step loss, and rare “2” results 2 step losses as the most possible.  Fire DG results now disappear at in each clean up phase, however, including DG to non-phasing units.  Small bombardments supplied from the same SP location or HQ can be paid for together as shown in the table.

Artillery units in Move mode that fire barrages count double their barrage strength for determining the supply cost of a bombardment, while resolving the barrage only with their printed Move mode barrage strength.  Mixed barrages (by some Combat and some Move mode units) total the payment and resolution sizes separately.

New barrage table

Bombardments by only 1 factor or less are ineffective and cannot be made.

2-4 need 12 to DG, cost 1/4T*
5-7 need 11-12 to DG, cost 1/2T*
8-11 are 10-11 to DG and step loss on a 12 only, cost 1T
12-16 give 9-10 DG, 11-12 DG and 1 step loss, cost 1T
17-24 gives 8-9 DG, 10-12 1 step loss, cost 2T
25-40 gives 7-9 DG, 10-12 1 step loss, cost 2T
41-68 gives 6-8 DG, 9-11 1 step loss, 12 2 step losses, cost 3T
69-116 gives 5-7 DG, 8-10 1 step loss, and 11-12 2 step losses, cost 4T
117+ gives 4-6 DG, 7-9 1 step loss, and 10-12 2 step losses, cost 6T

* small barrages funded from the same HQ throw or direct supply pull location can share the same 1T spend for these small types. But round up to 1T increments spent at each supply source location.

The column used for a barrage start from the column given by the total bombardment factors used, but can be shifted right (higher) or left (lower) by the following factors –

6+ soft REs in the target hex – 2 columns right

6+ total REs in the target hex – 1 column right (not cumulative with the previous)

any units in strategic march mode in the target hex – 1 column right

no adjacent spotter for non-air attack – 1 column left

extremely close terrain – 1 column left

level 2 or higher hedgehog – 1 column left (not cumulative with the previous)

Only one barrage may be conducted against a given target hex in the same phase, with all bombardment factors fired against it being combined into one total before resolving the shot. Each firing artillery unit is “tapped” to show that it has provided support and may not do so again until it “readies” again at the start of the same player’s following movement phase.  Note this means artillery units that support in the friendly bombardment phase will not be available to give Defensive Fire Support in the immediately following enemy combat phase.

The losing player chooses his units to take bombardment step losses, but must take them from soft units if possible, and full strength units in preference to reduced ones until all units present have taken a step loss.

Barrages against facilities use the same procedures as original OCS.  Barrages may also directly target SPs in dumps using the facilities table, with each “1” result destroying 1 SP, a “2” result destroying 2 SP if present.

Night strike air missions may only use the facilities table and halve the bombardment strength of all participating air units, but may not be intercepted.  They are still subject to flak.

Interdiction missions (“trainbusting”)

Interdiction is similar to barrage against facilities but uses the following table

1-2 bombardment factors – 6 to place an Interdiction Zone marker

3-4 bombardment factors – 5-6 to place an Interdiction Zone marker

5-7 bombardment factors – 4-6 to place an Interdiction Zone marker

8+ bombardment factors – Automatically place an Interdiction Zone marker

12.11 Supply capture and evasion

Supply capture is deliberately made considerably harder in new OCS. The procedure used follows the mechanism original OCS 4.3 uses for airfield capture, with a 2D6 roll determining whether all SPs evade, 50% are lost and the rest evade, or 50% are captured and the rest lost.  There are 3 columns used for this, for truck lifted SPs, wagon lifted SPs, and SPs without sufficient lift.  Trucks can provide lift for twice their printed capacity, wagons only equal to their printed capacity.

Truck lifted SPs that successfully evade are placed up to 10 truck MPs closer to any friendly supply source on any dump legal hex (other SPs or combat units).  All other SPs that successfully evade are placed up to 8 leg MPs closer to any friendly supply source on any dump legal hex.

If partial lift exits, use only one die roll and apply the result first to the lifted portion using its column, then apply the same roll the no lift portion on the no lift column.

No lift means 2-6 50% captured/50% lost, 7-9 50% lost/rest evade, 10+ all evade

wagon lift means 2-5 50% captured/rest lost, 6-8 50% lost/rest evade, 9+ all evade

truck lift means 2-4 50% captured/rest lost, 5-7 50% lost/rest evade, 8+ all evade.

There is a +1 DRM to these evasion results if the SP hex was only cleared of friendly combat units as a result of a CRT result, whether in overrun, combat phase, or exploitation combat.

Truck and wagon points can also be captured in the same way, but only 1/2 of those present on the lowest rolls on each column, the rest being lost.

13.1c HQs in combat, evasion and regroup

HQs defending in combat are single step soft units with 3 defense in stationary and 1 defense in move mode.  If they must lead a defense they are considered AR 1 units.

HQ units that would suffer a step loss result from combat automatically attempt to evade using the supply evasion procedure, which will always benefit from the DRM for combat.  If their movement side MA is greater than 10 they use the trucked SP evasion column (succeeds on 7+), otherwise they use the wagon lifted SP column (succeeds on 8+).

An HQ that successfully evades relocates up to 10 truck MPs or up to 8 leg MPs closer to any friendly supply source depending on its evasion type.  Successful evasion negates any step loss result to the HQ, including any due to retreat through EZOC.  If an HQ suffers a step loss and fails its evasion roll, that HQ is eliminated and become eligible for rebuild from replacements normally.

13.4 Artillery in ground combat changes

Artillery units may defend in ground combat with 1 DF for 1-14 bombardment factors, 2 DF for 15-24 bombardment factors, and 3 DF for 25 or more bombardment factors.  Artillery unit DF is always 1 in Move mode. They may provide defensive artillery fire vs attacks on their own hex if ready and they have sufficient bombardment strength, paying 1T to do so.  Artillery units are 1 RE, 1 step combat units for all other purposes.

13.7 Formations and Formation Integrity changes

In new OCS, normally attackers must use the lowest quality rating among their attacking units, not that of a single chosen lead unit.  Defenders use the highest quality rating among their defending units.  However, if all combat units of the same formation are participating in the same ground attack – from one hex or from several – then the attackers may use the highest quality rating of any unit in that formation for the whole attack.  This Formation Integrity benefit is available even if units from outside the formation also participate in that attack.

Smaller formations, such as German motorized infantry divisions and some brigades that have formation counters (e.g. in DAK) only cost 2T to fuel for a game turn.  Full sized armor division or tank corps formations cost the full 1 SP to fuel for a turn as in original OCS.

Comments – both aspects of the “sharing” of unit quality levels encourage keeping mobile formations together instead of scattering them to “lend” their AR ratings to other units.  The lower fuel cost of motorized divisions encourages using them along with full panzer divisions instead of making it prohibitive in supply efficiency terms to regularly fuel these weaker formations.

14.0 Air operations phase

All air operations are centralized into an air operations phase at the start of the player turn instead of being spread throughout the turn.

Aircraft refit – costs 1T per fighter squadron and 1T per 12 bombardment factors for bomber units to move air units from inactive to active status (from below to above their airfield marker).  Refit limit is 2 units per airfield level as in original OCS.

Assign air unit missions – fighters can sweep, escort, day strike, interdict, be placed on patrol, or left ready at their airfields.  Bombers can day strike, interdict, or night strike for 2+ engine bomber units only.

Resolve fighter sweeps – sweep fighter conduct air to air combat vs enemy patrol or ready fighters.  Enemy bomber units are never affected by fighter sweeps and need not engaged in air combat with sweep fighters.  After air combat, all sweep fighters return to their airbases inactive.

Interception – non-phasing patrol fighters may intercept any strike within 10 hexes; ready fighters must intercept any strike at their own airbase and may intercept any strike within 20 hexes.  Any number of eligible fighters may intercept any given day strike; night strikes may not be intercepted.  All interceptions are assigned before resolving any.  Then intercepting fighters conduct one round of air combat vs their intercept targets.  After air combat, all intercepting fighters return to their airbases inactive.

Strike – resolve all day strike then all night strike missions, using the bombardment table vs ground units and the facilities table against all other targets.  Enemy SPs may be targeted on the facilities table, which each “1” destroying 1 SP, “2” destroying 2 SPs from one dump.  Night missions may only be conducted on the facilities table, never vs ground units, and halve the bombardment rating of all involved bombers.  After all strikes, roll for flak losses to each strike mission.  Only strike missions (day or night) suffer flak.  There is no short range right shift for bombardment missions.  Inactive air units and active bomber units at an airbase are subject to step loss for facilities table hits.

14.2e change – strike missions can only be conducted once against a given target hex in a single air operations phase.  There are no “hip shoots” and no repeated missions until one has obtained a desired result.  The 4 unit per mission “stacking limit” still applies.  Strike packages containing 3-4 air units suffer +1 to their flak result (1 step loss on 10-12 therefore), missions containing 1-2 units roll normally (1 step loss on 11-12 only).

Interdiction – An interdiction mission requires can be placed automatically if at least 8 bombardment factors survive any interception attempts.  Fighter units (any with non-parenthesis air combat rating) have their bombardment rating doubled for Interdiction mission purposes only.  (So e.g. a single full strength Me-110 group can create an interdiction zone by itself).  Interdiction attempts with fewer bombardment factors can be attempted and succeed on a single die “6” for 1-2 bombardment factors, “5-6” for 3-4 bombardment factors, and “4-6” for 5-7 bombardment factors.

The affected hex and all adjacent hexes are Interdiction Zone hexes.  To enter an interdiction zone hex costs +1 MP for all units in Move mode, and they must also pay 1 MP per road hex.  Supply throw also pays these higher costs, but never more than half an HQs listed throw range.  Wagons and trucks also pay these costs, but if they use only 1/2 their MPs to move on the map may ignore all interdiction zones that turn.  They may still pay 1/2 their MPs to change to or from Extender form that turn, as well.  To be clear about it, transport units pay extra Interdiction movement costs only if they use more than 1/2 of their movement allowance to move on the map and to load or unload SPs.

Units in Strat mode may not enter an interdiction zone at all.  The center hex of an interdiction zone is also blocked for Rail cap movement.  Units in Combat mode are not affected by Interdiction Zones, and trace supply is never blocked by them.  These costs are not cumulative with ZOC movement costs or each other if zones overlap; pay only the highest single penalty.

Transport – air transport missions are conducted in the air operations phase, not in the movement phase.  SPs may be moved by air at this time, but cannot “leapfrog” later in the turn.  Ground units moved by air in the air operations phase can move 1/2 their MA in their normal movement phase only.  Air transport can never move units in Reaction or Exploitation.

At the end of the air operations phase, phasing air units that conducted any mission except patrol or interdiction are all returned to their airbases inactive.  Patrol and interdiction units remain on the map until they conduct an intercept during the enemy player turn or until the enemy’s clean up phase.  Note that a readied air unit that did not conduct a mission will remain active and need not be readied again to be used on a following turn.

14.3 Air combat – the air combat procedure is changed considerably, which each attacking air unit fighting only once in a given air combat and the combat concluded as soon as each has done so.   Defending fighters are the only air units that will ever conduct more than one air combat in the same phase, whether defending a strike against intercept or a patrol or ready airbase fighter vs a fighter sweep.

In a fighter sweep mission, the phasing player’s sweep fighters are always the attacker and a non-phasing patrol or airfield located ready fighter is always the defender.  Each attacking fighter in sequence conducts 1 air combat round against a defending fighter unit, using the normal air combat procedure.  Regardless of the result, any surviving sweep fighter is returned to its airbase inactive immediately afterward.  Any surviving defending fighters remain where they were; aborted ones are of course returned to their airbase inactive.

In any intercept mission, the non-phasing player’s intercepting patrol or airbase ready fighters are always the attackers, and the air units in the targeted day mission are always the defenders.  If those include escorting fighters, the intercepting fighters must attack them first, and cannot attack any other mission units until all escorting fighters have been aborted.  Each attacking intercepting fighter is returned to its airbase inactive immediately after its air combat round.  Any defending escorting fighter remains where it is unless and until it is aborted by an air combat result.  If all escorting fighters have been aborted or there were none, the mission player must offer another air unit to fight each remaining attacking intercepting fighter.  Again the attackers return to their airbases after their one combat round, while mission units continue their mission unless aborted.

Clarification – the third “loss” die for aborted side step losses will cause both sides to take 1 step loss if the original result is “both abort” (modified “7”).

Note that ready bombers at an airbase cannot be forced into air to air combat by a fighter sweep.  Fighters may strike the base with their bombardment rating, but that is a different mission.  Fighter sweep initiated air combat is never voluntary for the defender, always forced, but all interceptions are voluntary.

14.4 Flak changes – Flak is only resolved after missions are finished, and only against strike missions, both day and night.  There is one roll for the whole mission, normally 11-12 for 1 step loss for strike packages of 1-2 air units and 10-12 for 1 step loss for strike packages with 3-4 air units.  There is a further +1 DRM for airbase strike, only, vs level 2 or higher airbases, only.

There is no flak modifier for being in a fighter patrol zone.  Air transport and transfer missions are not subject to flak but can be intercepted by patrol or air base ready fighters within range like all other air missions.

Miscellaneous Changes

Hedgehog construction 16.0b costs only 1 SP per level instead of 2 SP per level

But notice, it now takes a level 2 hedgehog to confer one left shift on the CRT and the bombardment table, and level 4 to confer two left shifts on the CRT, and still only 1 left shift of the bombardment table.  Thus is takes more time but the same SPs to reach the first level of improved positions benefit, and the maximum effect of hedgehogs is “capped” lower than in 4.3 OCS.

No other changes.

Supply Summary Changes

Air refit – Readying air units costs 1T per fighter unit and 1T per 12 bombardment factors of bomber units readied at that air base, rounding normally.

Combat supply – attacker pays 1T per 2 attacking steps, round up to nearest T.

Defenders pays 2T per combat for 3+ defending steps, 1T for 1-2  defending steps.  May withhold supply fighting at 1/2 DF.

Defensive artillery barrage costs 1T and requires ready artillery unit(s) in range with at least 12 bombardment strength; gives -1 DRM both side of CRT.

Internal stocks – costs 1T per step to remove Low, 2T per step to remote Exhausted markers in the friendly supply phase.

Barrage supply – use the (lower) supply cost line on the revised Barrage table, as before.

Supply Draw never pays extra MPs for Interdiction or ZOCs.

Supply paths other than Draw count ZOC and interdiction costs, but friendly combat units negate EZOCs for all supply path purposes.

Supply throw can ignore Interdiction MP costs if using only 1/2 the HQs rated Supply Throw distance.

Fuel supply – some smaller Formations (e.g. German motorized infantry division, some brigades) pay only 2T for a fuel marker.

Hedgehogs – cost 1SP per level but only have combat effects at levels 2 and 4.

No other changes.

This ends the changes to the OCS series rules.

Smolensk – Barbarossa Derailed game specific changes

These rules effectively increase the supply available to both sides to approximately the “convention tempo” optional rule.  This is justified given historical op tempos in this period, based on a careful accounting of the amount of moving and fighting both sides conducted during the battle of Smolensk, as documented in Glantz.

Weather and air

The weather roll of 1 is treated as days of thunderstorms and overcast with the following effects.  These replace the “Limited Flight” rules on the weather table (basically already in effect by series rule changes).

On limited flight turns, single engine strike planes don’t fly missions – Ju-87, IL-2, SB-2. Heavier bombers and transport planes can fly missions normally, but cannot perform interdiction, and all day bombardments suffer 1 shift left on the bombardment or facilities table. Night bombing is not affected (just bombardment factors halved as normal). Fighter units can fly sweeps, patrol, escort, intercept normally, but no strike or interdiction missions.

German supply changes

All the 4 and 5 SP starting German dumps are 10 SP.
The one 10 SP starting German dump is 20 SP.

The single hex with 2T becomes 1 SP (at the airfield on the western map edge).

Note this raises starting German supply counting organic trucks from 39.5 SP to 73 SP, about enough to fund 2-3 turns of high tempo operations out of starting stocks.

German supply train special events are 4 SP instead of 2 SP.

German rail cap becomes 2 on the July 19 turn, it is 0 before then.

12 Jul K transport is 5 truck, 5 wagon loaded (+2 of each).
All other transport reinforcements +1 each location and type (6 truck and 2 wagon all told)
Add 4 to all Early Axis Supply Table amounts (become 7-15)
Add 2 to all Late Axis Supply Table amounts (become 3-7).

Russian supply changes

Increase starting Russian supply amounts by 50%, leaving all locations with 1 SP unchanged.  Increase their transport amounts by 1 in locations with 2 or more wagons or trucks (excluding their starting wagon extender), leaving all places with 1 unchanged.

Add 2 to all of the Soviet Supply Table results, so the Early period runs 7-11 with 9 expected and the Late period runs 3-7 with 5 expected.

For the removal on 19 August, increase the withdrawn transport to 3 truck and 5 wagon points (+1 to each).

1.2 Rail changes

Initial Russian rail cap is 2, and it becomes 4 on the July 19 turn.

Initial German rail cap is 0, and it becomes 2 on the July 19 turn.

1.3 Hedgehogs

The starting hedgehogs on the map are all level 2, the first level that gives combat and barrage benefits.  These hedgehogs are removed as soon as their hex is entered by any German unit.

Neither player may build hedgehogs beyond level 2.  Russians may not build new hedgehogs until turn 8 (August 1 turn), using the normal new series rules (1 SP per level, no combat effect until level 2).

1.4b Edge Boxes

First, some higher AR Russian units can use Strat mode after the first turn, according to the normal new series rules.

Russian units that move into either edge box using Rail Cap may be moved to the other edge box the turn they exit, and may enter the map the following game turn from that box in Move or Strat modes only.

Russian units that move into any edge box in Combat, Move or Strat move mode must remain in that edge box.  They may enter from that edge box the following turn in Move or Strat modes only.

Russian units in one edge box can be moved to the other edge box only by using Rail cap, and it takes them their turn to do so.  They may enter from the new off map box only on the following game turn.

1.6b “Extra” air supply

Air transport does not get “free” supply, it must draw from off board box SP totals arriving via the supply table or stockpiled there.

2.1 Supply arrival

The Supply table arrivals for each player are increased as explained in the first section above – +4 for the Germans in the early period and +2 in the late, and +2 for the Russians throughout.

2.2 Red Air Force

Double all ranges for all Russian air units (this deliberately “undoes” the game specific low ranges the original designers used to “nerf” the Red air force).  See Luftwaffe below for changes to German Me-109 air combat ratings that reflect the pilot skill differential in this period.  Soviet MiG-3, LaGG-3, and Yak-1 fighters all receive +1 to their air combat ratings on full strength and reduced sides.

2.3b The NKVD

There aren’t any optional losses anymore, but high AR rating NKVD units must be the first step loss in all defenses.  Their rating won’t be used in attacks by the ordinary series rules and their parentheses combat rating.

2.3c Frontal Reserves

SP arrivals for the Front Reserve events are increased to 8 SP.

2.3d Soviet Artillery

Soviet artillery does need to be in the same hex to combine into a single barrage attack, but multiple barrage attacks on the same target hex in the same phase are not allowed.  Fire elsewhere or do not fire.

Soviet artillery barrage values are halved after paying barrage costs but before rolling on the table.  In addition, to earn a -1 DRM for Soviet defensive artillery fire requires 24 bombardment factors instead of 12.  This reflects limited Soviet ability to communicate, coordinate and deliver accurate indirect fires in this period.

2.3e Operational Limits

No Russian units may use Strat mode on turn 1, but they have full movement allowance that turn. On turns 2-7, only Russian units with quality 3 or higher may use Strat mode, within the series rule restrictions. Quality 0, 1, and 2 units may not use Strat mode until turn 8 (beginning of August). (Exception – all units of the 1st Motorized may do so, including its artillery regiment and its single AR 2 armored unit). Starting on turn 8, all Russian units may use Strat mode normally.

Note to the German player – if you want to prevent the better Russian units using Strat mode early, you will need to fly Interdiction missions with your Luftwaffe or threaten to penetrate to their locations. Strat mode units cannot enter an Interdiction Zone, and their combat strengths are halved below the Move mode levels.

3.1 German Supply Arrival

2 SP of Supply table arrivals can be placed in each detrainable city hex, up from 1 SP.  Supply table arrivals are also substantially increased as per the first section above.  German Supply Train special events now give 5 SP rather than 2 SP, which must be placed in a single detrainable city hex.

3.2 Luftwaffe and air

Per new series rules, there are no Hip Shoots.

All German Me-109 fighter units receive +1 to their air combat rating on both their full strength (now 5) and reduced (now 4) sides.  This also includes the “mixed” 3-3 group, which becomes 4 at full strength and 3 at reduced strength.  This reflects the pilot skill differential in this period.

Russian MiG-3, LaGG-3, and Yak-1 fighter units receive +1  to their air combat rating on full strength or reduced sides.  This reflects their superior speed to the other Russian types and keeps them in line with the change above, in relative terms.

3.4b Guderian and Hoth supply restrictions

Supply table arrivals must be split between Guderian and Hoth within a 60-40 ratio each turn.  Off map west edge boxes must be maintained for each of them separately, and transport units may “draw” only from the northern Hoth box when drawing supply from an entry hex north of the dividing line, and must “draw” from the southern Guderian box when drawing from an entry hex south of the dividing line.

Luftwaffe units in the west edge boxes may “draw” from either box as they see fit, both to fund their own operations and for Ju-52 Transport missions carrying supply onto the map.

Supply train events are in addition to the above and do not need to be taken into account in the 60-40 split requirement.  Initially the only German controlled detrainable hex is in the south, within Guderian’s sector, so all early Supply Train events will wind up benefiting his panzer group.  Supply cache counters can be used anywhere without restrictions.

Other German special rules

The IR GD and Lehr Brigade motorized infantry units are 2 step units for all purposes.  They have 10 strength in combat mode and 5 in move mode, half the strength of a 4 step German infantry division, so they deserve the same 2 step size treatment as “half a division”.  This also means they have ZOCs when in combat mode even alone, which is historical for the frontages they were assigned during this battle.


The Russians have full movement allowance on the first turn in all scenarios.  They may not use Strat mode on the July 8 turn in any of the campaign start scenarios.  That is their only turn 1 restriction.

Terrain overrun restrictions relaxed

A further point about this after more Glantz reading and playing out openings of the Smolensk game. It is clear that the original OCS overrun terrain restrictions are simply too tight for the 2 turn per week time scale. In practice, a single regiment or half division on a scrap of marsh can hold up a panzer corps for most of 3.5 days simply by the phasing, due to the prohibition against overruns against their occupied terrain type. In the real deal, single panzer divisions blew through such positions in hours, on days they advanced 10s of kilometers.

The only terrain type on the Smolensk map that ought to prohibit overruns are the major rivers. For everything else, the restriction to 1 overrun attempt per target hex per movement phase, and each moving stack only able to conduct 1 overrun per movement phase, are sufficient to hold op tempo to reasonable levels (along with supply and loss rate limitations etc).

There are a number of little “puzzles” set at the opening of the Smolensk campaign in the form of little Russian “roadblock” positions, and fun as it is to find ways to turn those from behind or exploit OCS phasing to get them out of the way in the combat phase and reserve exploit after etc. But e.g. in the north, Hoth blew through the Dvina crossings in hours and was attacking north of Vitebsk and at Vitebsk by later on the same day. That is overrun stuff in OCS terms, not spending most of the 3.5 day turn getting through a regiment in a marsh.

The only change needed here is just that the “no overrun” terrain restriction becomes limited to “no overruns across a major river hexside”. For other games / modules, no overruns into mountain terrain would be added, but that’s it.

I should also say I conducted a successful major playtest of this system at Consimworld 2019, using the specific game “Smolensk – Barbarossa Derailed”, one of the most recent titles in the series.  I previously played this game 5 times on Vassal with playtesters using the new rules and tuning the amount of supply provided.

Burma module special rules

Banzai attacks

Japanese attackers may declare Banzai charge attacks at their discretion.  When a Banzai is declared, all aspects of the combat are resolved normally except the Surprise procedure.  The chance of both Ambush and Attacker Surprise are increased by 1/6 each, with a white “1” always Ambush, even for DG defenders or defenders with much lower AR or both.  If there is no Ambush, Attacker Surprise is also 1/6 more likely, thus 5-6 with AR levels within 1, 4-6 for Japanese AR 2 levels of more higher, and Attacker Surprise occurring on red 6 even with attacking AR level 2 or more below defender AR level.  However, Attacker Surprise never reduces attacker step losses in Banzai attacks.  Instead it always increases defender retreat requirements by 1 hex and causes 1 defenders step loss if there were no defender step losses on the original combat table result.  Defender step losses are never increased further if they already lost a step in a Banzai attack result.  Note that step losses for retreat through ZOC are assessed later and separately, and a Banzai attack may indirectly force an additional step loss if it forces a retreat through ZOC. Banzai only applies to Japanese attacks, never to Japanese defenses.

Japanese hedgehogs

Japanese units may place level 1 hedgehogs when stationary as in the module specific rules without supply cost. They may complete these into level 2 hedgehogs – thus earning the first combat and bombardment table benefits – by doing so again on any following turn spent stationary, again without supply cost.  Japanese units may not build hedgehogs beyond level 2.  Allies may build hedgehogs normally by paying the normal full supply cost.

Small artillery units

There are a number of 3 bombardment strength units in the module.  Up to 4 of these may fund bombardments in the same phase by paying 1T, and the requirement that all such must be in throw range of the same HQ is lifted for this module.  The 1T may be paid from any hex that could fund any one of the firing units, provided that all have some T available within range in order to fire. Small artillery units contribute only 1 point of defense strength if their hex is attacked. 


Allied supply arrivals in campaign scenarios are +2 SP above the table entries.  Japanese supply arrivals are +1 SP above the table entries.  In shorter scenarios in which they would normally receive 2T per turn, the Japanese receive 1 SP per turn instead.  In scenarios in which the Allies receive 1/2 the supply table roll, they instead receive 1/2 the supply table roll plus 1 SP.  In scenarios in which the Allies receive a fixed SP allowance instead, raise that fixed SP allowance by 1 SP per turn.  All air unit readying pays full revised rule supply costs including off map airbases, and no air transport supply is “free”.   However, “hump  diversion” events do give extra new supply.  For each hump diversion, D6 roll of 1-2 gives 2T, 3-4 gives 4T, and 5-6 gives 6T.

Air missions, concealment and spotters

Ignore the module specific requirement to have a spotter for all air missions against hexes with concealment terrain (light jungle, jungle, and mountain).  Instead, shift all air bombardment missions against such hexes 1 column left, whether spotted or not.  During Restricted Flight weather, only air transfers and rebasing of air units may be performed, no other missions.

Overview of motives behind the system

New OCS is a full set of modifications to the extremely popular games series from MMP, a special favorite at large gaming conventions like Consimworld in Phoenix. OCS stands for the Operational Combat Series. This has far more detail about supply and logistics as well as unit operating “modes” than simple systems like SCS (“Standard” combat series), as well as a fully treatment of air operations and unit quality differences.

I introduced the modifications on the Board Game Geek site first, and you can find the main proposals in that original form in the following thread –

New OCS modest proposals

Here I will both summarize the changes and explain some of their motivations.


While I like the OCS series and find its detail and coverage of numerous important campaigns very impressive, I have always had problems with some features of the system that strike me as insufficiently developed or less than realistic.  I know plenty of OCS players have adapted to the rules as they have evolved (the rules are currently on version 4.2, so not exactly a static set), but most will tell you in private moments of their own issues with the series.  My goal is to use OCS as a base to redesign my ideal operational WW2 (and similar) era combat system.  I wouldn’t use it as that base if I didn’t like tons of things about the system, and my intention is to preserve its feel and major components.  But that doesn’t mean I want the same tactics to work in my revised system, or the new version to set up the same incentives and trade offs as the original.

I’ll start with some of my main issues with OCS RAW (rules as written).

Air ground coordination is too tight and “just in time” for the real level of such coordination in WW2.  Also, it is too focused on ground support rather than interdiction and supply-suppression focused missions.  And air units barely cost anything in supply terms, making them far more efficient than artillery as a firepower arm.  The opposite was the case in the real war – air could reach deeper and do things the guns could not, but front line fire support was better served by the artillery, which had better comms, coordination, loiter time, logistic thruput, and efficiency in a resources per firepower sense.

The supply limits of the system force players to unrealistic allocation tactics, starving their guns and the bulk of their infantry forces, fighting as little as possible and that with their highest rated armored forces almost exclusively.  The focus becomes getting around the enemy with as little combat as possible – all maneuver warfare dislocation rather than attrition fighting by the bulk of the force – with that “razzle dazzle” then limited by a very tight logistics “leash”.  I don’t find these incentives realistic.  I want combat and fire support from the bulk of the force to be more important and logistically cheaper, and bypassing enemies to defeat them just by “starving” them to be harder, than in the original system.

The HQ and supply system that players need to organize and manage effectively are critical to OCS and I want the administrative side of those things to change as little as possible, since it is a core game mechanic.  However, I don’t want it to be as easy to disrupt the other guy’s HQs and supply network as it often is in OCS RAW, especially the east front titles.  In those players frequently find themselves “telling off” entire maneuver force armies to guard and garrison every important position in their “backfield”, lest deep enemy penetrations simply overrun HQs and supplies and win the war effortlessly in that manner.

The game’s phasing strongly encourages this, along with its lack of normal zones of control (replaced in later editions of the rules with involved restrictions on “truck movement” near enemy forces).  Forces get to move and fight repeatedly before the enemy can move a muscle, and this means all backfield locations can be reached by a sufficiently dedicated drive.  While defense in depth and reserves should still matter, armies should not fold simply because someone drives behind them, nor should entire armies be forced to garrison every road junction for weeks at a time tens of miles from the front to prevent this.

Building on that point, the game needs a real ZOC system.  There are major scenarios in the east front titles in which the force to space is such that only units in every other hex are even possible, even without rear area garrisons.  These can then be penetrated without combat in movement phases, with combat only occurring after targeted units are already bypassed and surrounded.  This simply wasn’t how warfare on the eastern front worked in WW2.  It should be necessary to fight to pierce enemy lines, not just drive.

Similarly, the OCS 4.3 very weak ZOCs system makes it infeasible to construct realistic pocket walls for cauldron battles of the type so important on the eastern front.  Using maps from Glantz, we can see how long the containment lines and exterior fronts were in some of these, and count out the formations used to form them.

In the Smolensk battle, 8 panzer divisions plus 5 motorized divisions with 2 attached single motorized regiments held in the Mogilev and Smolensk pockets and the entire eastern face of the AG center position, over a distance of 75 hexes held by strong enough forces to prevent any Russian passage, with another 25 screened lightly or left as gaps along that line.  The Smolensk title has 58 single step combat units in those German formations, plus 13 mobile division artillery regiments.  Stacked 2 to a hex and using their artillery in some of them (never alone) the Germans can form 34 positions with sensible tasking, which get real ZOCs in the revised system, and which will therefore hold a front that long, though none to strongly in places.  But with only RAW 4.3 ZOCs, which foot and tracked units ignore even in Move mode, there is no way for those formations to hold in 30 Russian divisions inside pockets behind them, while holding frontages that long.  Even if you spread them 1 per hex, they physically could not line the frontage.  So, real ZOCs that block movement by combat units are needed for step-count to frontage realism.

Next to combat.  The RAW combat system has a very involved resolution procedure in which 4-5D6 are needed to resolve each, in 2-3 sequential rolls for combat type, surprise modification amount, and final combat resolution.  Unit quality levels have huge effects on both the battle type / surprise system and the combat step itself, to the point where single battalions with a high quality rating can routinely defeat stacks of enemy divisions attacking them.  And the results are very “swingee”, very long tails of binomial chance, with events as infrequent as 1 in 7776 modeled.  These appear to be part of the designers intense desire to make combat unpredictable, but I both find it unbelievable and strongly disagree with the design intent to frustrate all attempts to plan combat outcomes.  I also just want to clean up and speed combat resolution.

In addition, the RAW combat results table (CRT) has a structure that reflects a Lanchester square law expectation of the effects of higher odds on combat losses, and includes large portions of its results in “optional” form, meaning the side suffering them can choose to take them as step losses or hexes of retreat.  Normally wanting to choose the latter, unless the units are surrounded, but including more sequential “fiddle” of attacker choosing how to take his optional results before the defender chooses his, which require multiple changes in control to resolve almost every combat.  This not only kills Vassal PBEM play, it again wrecks planning out expected results of combats, and gives sides an ability to dial losses lower in return for ground ceded far in excess of what I consider realistic.

The combat scaling of the original CRT increases defender expected losses by 7/6 and reduces attacker expected losses by 5/6 each odds column right or positive DRM, meaning the expected loss ratio moves 1.4 times for each such change, and double for each 2 columns or DRMs.  This means attackers can protect their forces by driving the odds ratio higher, so that spearheads that fight at high enough odds receive no significant “wear” from doing so.  The main limitation on high odds attacks in preference to all others tend to be logistic rather than combat table related.

But then in addition, the cross over point where attacker losses and defender losses are about equal are located between the 3-1 and the 4-1 odds columns, which is 2 columns right of where empirical research on WW2 battles shows that “even losses” expectation cross over point to be.  The RAW CRT is only realistic in a relative losses sense if all real WW2 defenders were halved (DGed before battle), effectively.  The effect is again to encourage very limited use of combat in only the most important situations at the highest odds, discouraging most of the force from fighting on most game turns.  I don’t find this realistic at all, especially in the force attrition relationships its sets up between strategic attackers and defenders.  I’ve seen full scale east front games in which multiple Soviet fronts attacked for weeks and only suffered rifle division step losses you could count on one hand in the process.  Why?  Because they never almost never paid SP to attack with them, and they never led an attack because all supply went to attacks led exclusively by the highest AR units.  That’s just not how the Red Army fought.

There are other minor points in a realism sense.  To simplify the effects of loses, the RAW has all units at 50% of their full steps or less fight at -50% strength, but all 3-4 step units down a single step fight at full strength.  They should instead lose 4 CF on their combat side, 2 CF on their movement side, for such first step losses.  Combats get to use the highest AR factor of any engaged unit, so a 1 AR Russian tank corps becomes 3 times as effective if assisted by a small motorcycle battalion of better trained troops.  There is no unit integrity system, so the incentive is to split up Panzer divisions into tiny packets to enable every “5” rated battalion to “lead” infantry divisions, “lending” them their quality. All of these need to be addressed.

There are also some major issues with the sequence of play, which features no less than 3 bombardment phases for the active player and 1 for the inactive player per half game turn.  (This is only partially mitigated by supplies so tight most possible barrages just aren’t fired).  Defending reserves react after movement but before combat, thus “pancaking” to the line to throw off attacker designed odds (again the mania to make combat unpredictable), but then can’t plug holes created by combat.  Units check supply before their own movement, so anything isolated by an enemy penetration has no chance to move or fight its way clear before being rendered out of supply.  Air units for some sides and scenarios are allowed to “hip shoot” repeatedly at the same target hex until they achieve the result they wanted, and to interleave this with movement and overrun attacks, as though each spearhead could call air artillery to neutralize enemies frozen in place for half a week at a time.  And the RAW allow for changes of the first player from turn to turn, allowing “double moves” on top of movement, combat, and exploitation phases, frequently used to engineer deliberate larger operations during which the enemy is effectively frozen for a week straight, before they get to react.  All these again need toning down to reflect a more realistic range of operations possible before the enemy can react to the last thing the active player just did.

I have also found that “spoiling barrage” tactics of just DGing all strong enemy formations in range every turn are unhistorically effective in standard OCS, especially in shorter scenarios.  I don’t find this in the actual history.  Whole Panzer divisions are not taken out of the fight for 3-4 days at a time by a single corps fire artillery barrage.  My revision increases the opportunities to use artillery in particular to fire for DG effects, thanks to more generous overall supply.  My solution is for fire DG to go away in each clean up phase, instead of lasting through the other player’s entire turn.  Fire for step losses are still possible, as well as following up with attacks or to neutralize enemy reserves temporarily.  The other defensive use of artillery is the new -1 DRM for defensive artillery support.  I find that this combination allows guns to be used for both attack and defense, but in a far more realistic manner.