OCS Series Rules, 4.3


Series Design: Dean N. Essig

Playtesting and Proofreading: Perry Andrus, Marty Arnsdorf, Matt Bace, Ranier Bastian, Dave Benjamin, John Best, Dirk Blennemann, Doug Burrell, Stephen Campbell, Tom Cannon, Don Charuk, Carl Chatto, Brenden Clark, Bob Cloyd, Dav Combs, Dave Demko, Chris Dodd, Karsten Droste, Sara Essig, Anders Fager, Andrew Fischer, Christophe Foley, Dave Friedrichs, Owen Fuller, Tom Gallinger, Don Gilbertson, Mike Haggett, Dirk Heinz, Paul Herkes, Nolan Hudgens, Roger Hyman, Michael Junkin, John Kisner, Tom Klubi, Roland LeBlanc, John Leggat, Christoph Ludwig, Charles McCallum, Ethan McKinney, Dave Mignerey, Rod Miller, Bill Moody, Maurício Moutinho, Don Nesbitt, Brian Niffin, Elias Nordling, Mark Pitcavage, Steve Poitinger, Barrie Pollock, Dave Powell, Dave Reynolds, Henk Roelant, Ernesto Sassot, Boyd Schorzman, Bernard Sperling, James Sterrett, Russell Stewart, Jim Stravers, John Strycharz, Michael-Peter Sturz, Roger Taylor, Giovanni Toletti, Kevin Valerien, Ric Walters, Al Wambold, Bruce Webb, Jim Wise, and Tony Zbaraschuk

v4.0 Rewrite Team: Perry Andrus, Jim Daniels, Dave Demko, Dean Essig, Andrew Fischer, Michael Junkin, John Kisner, Hans Korting, Roland LeBlanc, and Rod Miller.

v4.0 Final Editor: Dave Demko

v4.0 to v4.3 Honcho: John Kisner, who coordinated all the efforts and did much of the heavy lifting. Thanks, John!

v4.3 Special Thanks: Gary Wright (for charts) and Mathew Hinkle (for edits).

Special Assistance: The Burrito as Big as Your Head, without which this system wouldn’t be what it is today.


Multi-Man Publishing, Inc. 403 Headquarters Drive, Suite 7, Millersville MD 21108 © 2018 All Rights Reserved.


Learning OCS is tough (for me). There are a lot of rules. I created this web-friendly version of the rulebook for my own personal use. I find the hyperlinked references to other rules/sections on a device-friendly, responsive website to be very helpful and minimizes having to flip through pages in the rulebook constantly. I hope The Gamers will implement something like this in the future! That said, the authors (Mr. Dean Essig and company) have produced an incredibly well-written and technically concise rulebook.

I have modified this online version of the rulebook to suit my own needs

  • Example: I have dramatically added to the Sequence of Play (2.0). Steps include hyperlinks to relevant sections and color helps me visualize where combat can occur by the phasing (red) or non-phasing (blue) players. I tried to design the sequence in such a way that it is my “homescreen” or “main hub” for rules when I sit down and play. Combining hyperlinks and the “back button”, I can easily navigate to important rule sections and back quickly and easily.*


  • OCS Series Rules v4.3 (PDF)
  • Charts and Tables v4.3 (PDF)
  • Turns Checklist (PDF)
  • Consolidated Errata (PDF)

See OCS Depot for the official (upcoming) new archive for OCS from The Gamers.


Operational Combat Series (OCS) games simulate campaign-level combat from 1900 to the mid-1950s. The series goal is to allow a sophisticated study of historical events while maintaining mechanical simplicity.

Version 4.3 Rules

The v4.3 rulebook is a minor revision. Some rules have been clarified and errata has been corrected. Small changes are marked with a √. Note the chart booklet was given a complete makeover, but is functionally the same as the previous versions (so feel free to continue using them). Enjoy!

Note that some terms were changed in the move from v3 to v4. Strategic Move Mode was shortened to Strat Mode, Combined Arms Effects was replaced by the more descriptive Anti-Tank Effects, and the old Railroad Interdiction and Interdiction effects were combined into the new Trainbusting mission. Keep these changes in mind when playing older games in the series.

Game Components

The Game Map

The map depicts the area in which the campaign was fought. Laminate the map or cover it with 1/8” Plexiglas to help protect your gaming investment.

The Hex Numbering System.

Each hex is identified by a unique four-digit number in the form “column.row.” If a game has more than one map, a letter identifies each, and the hex numbers for hexes on a given map are prefixed with the map’s letter. So “B10.10” identifies hex 10.10 on Map B. The digits before the decimal point identify the hex row, reading along the horizontal dimension from left to right. The digits after the decimal identify the exact hex in that particular row, reading along the vertical dimension from bottom to top. Only every fifth hex has a printed number (xx.05, xx.10, xx.15) to create grid lines. For example, to find hex 29.17, follow the grid line for xx.15 until you find the 29.xx hexrow, then count up two hexes to 29.17.

Map Edge Hexes.

A hex is playable only if at least half of the hex is showing.

Off Map Movement.

Unless it is specifically allowed in a game, units can neither exit the map to re-enter later nor conduct any off-map movement. Destroy units forced off the map.

Turn Record.

A turn record track is printed on the map or play aids. Each box represents one game turn. (See 2.1)

Weather Record.

Mark the current weather on this track.

Holding Boxes.

There are two types of holding boxes, those corresponding to a specific hex and those showing an abstract off-map location.

  • Specific-hex holding boxes are used to relieve congestion on the map. The units are considered still in the hex associated with the box.
  • Off-map holding boxes can hold an unlimited number of units. Gamespecific rules will restrict these boxes to one side or the other, and describe how units move between them and the map. No combat is allowed.

The Counters

Carefully cut or punch the cardboard counters from the sheets and keep them organized (baggies work nicely) by side, type, and identification. This will make setup easier. The various kinds of units and markers are described in 3.0.

The Rules

An OCS game contains both Series rules and Game rules. The Series booklet has the rules that apply to all OCS games. The Game booklet includes special rules, scenarios, and set-up information for the specific game.


Rules are numbered by section and case. Each major rules grouping is a section; each paragraph within a section is a case. The number 6.2 would, for example, refer to section 6, case 2. A specific case may contain a number of statements that are lettered, as in 6.2a and 6.2b.


Repetition. Once stated, a rule is repeated in another section only when needed for clarification in that section.

Set Up Notes

In the Game rules is set-up information for the scenarios. Unless amended by special instructions in that booklet, the following are always true:

  • A) “w/i X” means to set up a given unit or stack at or within X hexes of the location given. A stack can “spread out” into multiple hexes within this radius (and possibly deploy breakdown regiments).

  • B) Ground units can be set up in any desired mode. (Exception: ground units adjacent to enemy AttackCapable units cannot be set up in Reserve or Strat Mode.)

  • C) Transport Points that are stacked with Supply Points (SP) can set up loaded or unloaded. Transport Points that are not stacked with SP always set up unloaded (unless the scenario rules specify otherwise).

  • D) Organic Trucks start “full” only if a scenario explicitly states that they do. (But they can take advantage of C above if they set up stacked with SP).

  • E) Aircraft always begin Active.

  • F) Units cannot set up over-stacked.

  • G) Units generally begin the game at full strength.

  • H) When the notation “(inclusive)” follows set-up boundaries, those units can set up anywhere within the zone including the boundary lines.

  • I) Units can never set up in a hex that they could not enter using regular movement.

  • J) Units, Formation markers, and HQs always set up “unfueled.”

  • K) Use index cards to create off-map areas for each side’s Dead Pile and to organize reinforcements.