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An OOB-Driven Game Design

Updated: Oct 6, 2023

Creating the Hub from which all other design Spokes radiate


Legendary game designer Frank Chadwick

By Frank Chadwick


From my earliest interest in military history and wargames, orders of battle (“OOB”) have fascinated me, and I think that fascination is constructive. Gross numbers of men, aircraft, tanks, and artillery do not really give you a good handle on an army. It is not until you start looking at how those assets are organized and deployed on a unit level that it all makes sense. You also can get a better insight into the reliability of those gross numbers that get tossed around.


For example, the total number of aircraft listed in an OOB may or may not be limited to serviceable ones. As importantly, the number of combat aircraft often includes all aircraft delivered to the Air Force, including spares, aircraft in training establishments, etc. It is not until discovering how many aircraft are in a combat squadron and then finding out how many actual deployed squadrons a nation has equipped with each type of aircraft that you really know the combat power of that air force. Believe me, the difference between the total aircraft of a type “on hand” and the total number of that aircraft in combat squadron service is often enormous.


So, partially because of my fascination with orders of battle and partially because of their utility in representing the capabilities of armies, our ETO series designs are OOB-driven. We started with the historic OOBs and then reverse-engineered them to develop the series’ production and replacement system. That system must be able to produce the historic OOBs, because if it cannot, players will complain, and justifiably so. I certainly would.


The German OOB Lens


The key order of battle in the game series, the hub of our project plan and the river that runs through every game, is the German OOB. Germany is the only belligerent with forces in every single game. Well, let me rephrase that: It is the only major power (or “Large Nation,” in ETO parlance) with forces in every single game. One other belligerent shows up with at least one unit on every front in the European Theater, from the very first battle to the end: Poland. They don’t always show up as game units in ETO, though, because we do not go down to Bigade level in this series, so the Poles in Norway and in North Africa (one brigade each) are subsumed in other larger units. But they are at Corps and Army strength levels in the East, Corps strength in Poland and Italy, and Division strength in France in 1940 and 1944. The Poles got around!


But back to the German OOB. It represents the clear majority of Axis units in the game, and they have an even more overwhelming proportion of the total Axis combat power. In a sense, the German Army is the Axis Army, with auxiliary allied forces fleshing them out in most theaters. Even in North Africa, where most Axis combat troops were Italian (and as a long-time student of the Italian Army, it pains me to say it), that single German Panzer corps unit (the Afrika Korps) is the only really effective offensive weapon they have on the ground for most of the African campaign.

Imagine this level of OOB detail for EVERY unit, Ground, Air, and Naval, in the entire ETO series. Yep...

The German OOB is not only the most important single one in the game, but it is also the largest and by far the most complicated (at least for those of us trying to make these games work). They sent units everywhere and often moved them between theaters (and often a single Division at a time). We had to track all those historical movements because we had to know who was where at the start of every scenario, and we had to know how those movements were achieved in game terms.


Consider that the Germans moved Panzer and Panzergrenadier Divisions around like crazy, but ETO is a Corps-level game; production is by Corps, not Divisions. So, we had to track which Corps units had to break down into Divisions, and when, and then track those separate Divisions through the game until they got someplace so we could reassemble them into a game-standard Corps unit! That means our OOB had to track German mobile troops on a Division-by-Division basis. And then we had to do the same with Mountain and Airborne Divisions, which also got redeployed like crazy. However, we put as many of them back into Corps units as possible for scenario setups to ease matters for players.


For Reference

So how did we do all that? The core document we worked from was one I originally assembled for a project (also to be called ETO) back in the days of Game Designers’ Workshop. John AsteIl and I worked on the game, but we were never satisfied with what we came up with, so we shelved the project. But I always kept that original OOB document. It is a month-by-month record of where every German Corps is from the start of the war to the end, along with their assignments to Armies or directly to the reserve of an Army Group. I assembled it by going through Georg Tessin’s Verbande und Truppen der deutschen Wehrmacht und Waffen SS im Zweiten Weltkrieg 1939-1945, starting with the higher commands and the listing of which Corps were with each Field and Panzer Army, month by month.


The seventeen volumes of Tessin’s Verbande und Truppen . . . (hereafter just Tessin) remain my principal sources on the German Army. Still, they are supplemented by a whole bunch of specialized sources on specific campaigns and some of the more exotic formations. This is especially the case with respect to scenario starting forces. Tessen’s monthly snapshot of Corps and Divisions assigned to Armies does not usually fall on the day of the start of a major operation, so he is always close to the mark. However, the historical shifting of troops from one Army to another right before or after an operation’s start complicates things. One additional source, in particular, deserves mention here: Dutch historian Leo Niehorster’s online resource, World War II Armed Forces – Orders of Battle. Unlike Tessin, he focuses on campaign starts and was invaluable in researching scenario setups. He is also very useful for the armed forces of smaller belligerents, who do not generally get the same amount of love as the Big Guys in most works.


The Color of Red


The second-most important ground army in the game is obviously the Soviet Army. For all of World War II in Europe (since technically it did not become a “world war” until the Japanese brought the United States into it and made it a global conflict), Germany and the Soviet Union were locked in a constant and continuous death struggle. The outcome of that struggle had as much or more to do with the war's final result than any other theater. Making the Red Army OOB “work,” from the production system's ability to produce those units at the same tempo as historically and in terms of modeling the army's performance with those game units, is a real trick. But I think we pulled off that trick pretty well.


The secret, of course, is, first and foremost, to have decent OOB research sources, and we had excellent material to work with. Man, I wish we had information this detailed and accessible back when we were designing the old Europa series games. The resource I relied most heavily on — and I cannot say enough in praise of this work — is the thirteen-volume Soviet Order of Battle, World War II by Charles C. Sharp, published by George Nafziger Press in 1999. Its coverage of Rifle Divisions, Specialized Divisions, artillery, NKVD, etc., and both tank and mechanized formations from Brigade up to Corps is top-notch.


The only thing really lacking is a detailed treatment of rifle Corps and field Armies (the level at which Red Army Rifle units are represented in the ETO series). They are above the level of Sharp’s work, and there is no reason they should have been included in these volumes — except that it would have made my life easier, particularly when it came to each scenario’s starting forces and deployments.


For that, I relied heavily on the series of books by Colonel David Glantz on the Red Army and the War in the East. His short book on the overall war in the East, When Titans Clashed (1995, University of Kansas), co-authored with Jonathan House, has a good set of appendices and a concise but very useful section on Soviet force generation. His more detailed work Colossus Reborn, The Red Army at War, 1941-43, (2005, University of Kansas) and its separately published additional appendices are invaluable for understanding how the Red Army was rebuilt during and after Barbarossa and how it fought. Glantz is one of the top global scholars on the Red Army in World War Two, and it shows in these volumes and others too numerous to list here, but many of which sit on my bookshelf as I type this.


Managing The Empire


Next up is the British Army and its Commonwealth allies. The British Army was the only Allied army that was at continuous war with Germany, from the invasion of Poland in 1939 to the German surrender in 1945. After the collapse and surrender of France, Britain had no realistic prospect of winning the war, yet it soldiered on in the hope that additional allies would appear from somewhere. Of course, the two “somewheres” were the East and North America. Britain could do nothing overtly to bring its other eventual major allies into the fray, but it could keep up the fight and hope for the best, which is what it did. Germany brought the Soviet Union in, and Japan eventually brought in the United States.

Immediately after Pearl Harbor, President Roosevelt cabled Churchill, "Today all of us are in the same boat...and it is a ship which will not and cannot be sunk."
Churchill recalled, "That night, I slept the sleep of the saved and thankful."

Britain had a tiny Army at the start of the war, and although it grew, it was never very big, at least compared to the size of an Army you would expect from an industrialized nation the size of Great Britain. There are many reasons for that, but the upshot is that the British Army leaves a small footprint in the game. Still, it has to fight in a lot of different places, usually with an interesting mishmash of British, Commonwealth, and Allied divisions. Because it must fight in France in 1940, defend Britain for a while, hold off the Afrika Korps in Egypt, invade Northwest Africa, Sicily, and Italy, and then come back home for Overlord only to fight in France again, they do a fair amount of theater-jumping. We needed to track that for the game OOBs in the stand-alone theaters and for Combined Games’ OOBs. Of course, we also had to make sure the OOB made sense in gamer terms and could reasonably be generated by the production system.

The starting point for the British Army OOB is, of course, Orders of Battle: United Kingdom and Colonial Formations and Units in the Second World War, 1939-1945 (2 volumes), by Lieutenant Colonel H. F. Joslen, published in 1960 in London by Her Majesty’s (now His Majesty’s) Stationery Office. Joslen is very complete for British Divisions and Brigades. It is an invaluable guide to who served with which Brigade when, and also when Brigades left one place and showed up somewhere else. Unfortunately, he covers only the British Army, not the Commonwealth or India, and his coverage of non-divisional units (Corps artillery and engineers in particular) is almost nonexistent, which is the great weakness of the work. Fortunately, that second part is not as important to a game at the scale we are working with, but the first part is a major shortcoming.


To the rescue came David Hughes and his co-authors (James Broshot, Alan Philson, David Ryan, and Steve Rothwell) with The British Armies in World War Two: An Organizational History, their eight volumes (and three OOB supplements) covering both the British and Commonwealth armies (Canada, New Zealand, Australia, South Africa, and India) in glorious detail. It is still a bit light on non-Divisional artillery, but since that is below the scale of this game, I can live with that. The volumes were published by George Nafziger’s press from 1999 on. Great stuff.


The British have a small enough Army that deals much more with Divisions than Corps, but ETO is Core-level game with breakdowns. Consequently, we had to do the same thing we did with the German mobile Divisions: track them individually and then reverse engineer a Corps OOB that made sense. Amazingly enough, it works well, even with such oddballs as the single horsed Cavalry Division floating around for a while, strange Corps-like formations such as the Western Desert Force, the various territorial commands, and the pre-war Mobile Force.


Other Newsmaker OOBs


The other big player in the West is the United States Army. Fortunately, the US Army is both extensively documented and in very accessible form. My core reference in this is Shelby Stanton’s amazingly detailed and complete Order of Battle, U.S. Army, World War II, published in 1984 by Presidio Press. The fact that no one (to my knowledge) has attempted to surpass or even replace it pretty much tells you what you need to know about its value.


In terms of the second tier of armies, the French Army of 1940 is well documented. Les Grandes Unités Françaises: Historiques Succincts, published in 1967 by the Ministere des Armées, É’tat-Major de L’Armee de Terre, Service Historique is very complete as to overall force structure, less so with unit assignments on the eve of the 1940 campaign. The French language site “France 1940” by Nowfel Leulliot fills that picture in very well, however, and has good coverage of L’Armee de L’Air (Air Force) and Marine Nationale (Navy).


Italy is well covered by a series of well-researched and written histories in Italian, a language I am not good at (to which my Italian friends will attest). Still, it has been well-mined by some researchers, and two books on the Italian Army by Jack Greene became my most-consulted sources: Handbook on the Italian Army in World War II: 1940-1943 (self-published in 1988) and Mare Nostrum: The War in the Mediterranean (also self-published, 1990). Leo Niehorster’s online resource was also very useful, particularly for detailed OOBs at the start of several campaigns.


OOB Honorable Mentions


Beyond these resources, I consulted various sources for the smaller armies, and I should mention the Osprey series of historical books on campaigns and their OOB series. When I first got into the game design biz, Osprey books were something of a joke. They were originally done mostly as painting guides, and when customers demanded more OOB information, they complied — but not very well. Some of their stuff was laughable, and I imagine it was embarrassing for them in retrospect. But that was then, and this is now. They have become one of the best sources for detailed, accurate order of battle information. Their volume on the Italian campaign in the Balkans has some great stuff, more detail than I had been able to find elsewhere. If you are interested in that campaign, it’s a must-have (despite the painting of an Italian soldier on the cover holding a grenade in his left hand, which is attached to his right arm!).


It is interesting (at least to me) that the authors of most of the books I rely on are also old pals of mine: Charles Sharp, Dave Hughs, Shelby Stanton, and Jack Greene. I have also shared a few speaking panels, discussions, and scotches with David Glantz. All of us are guys fascinated by orders of battle. You know what they say about birds of a feather.




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