Co-Prosperity Sphere:
Designer’s Notes
by Mike Bennighof, Ph.D.
May 2023

With our Great Pacific War: Co-Prosperity Sphere expansion, we bring our Long War setting to Great Pacific War, setting up a situation in which the Japanese Empire is far larger and far more economically productive than in our actual history. That provides the Japanese player with the forces and position to actually stand up against the American tidal wave, to actually win the game rather than see his or her forces crushed in a slightly longer time frame than the actual war lasted.

The concept had another attraction for me as the expansion’s designer. Brian Knipple’s original work on Great Pacific War is a fine game design; the simple underlying concept that ties together economics with battlefield results, all within an intuitive roll-a-six game mechanic, is truly brilliant. Great Pacific War shows how the war took place and why, working in the reasons for the historical events with a great deal of subtlety while remaining deceptively simple to play.

Yet by necessity the game has to incorporate a number of special rules to reflect unusual events like the American embargoes of oil and steel, the possibilities of Soviet intervention, the Japanese concept of limited war against China, the convoluted politics of the Chinese War of Resistance as the Communists and Nationalists waged war against the Japanese but also, on occasion, against each other. The designer must work in not only the things that happened, but those that the participants believed might happen even if in hindsight you believe them impossible – otherwise, the players won’t act under the same assumptions as their historical counterparts.

So for Co-Prosperity Sphere, I made all of those mechanically intricate game special events go away, writing the background to fit the most straightforward sections of the rulebook and rendering as many special rules as possible unnecessary. The Co-Prosperity Sphere scenarios aren’t dumbed-down versions of those in Great Pacific War – they use all of the same core rules – but they are far easier to play in practice and, as a result, play moves much faster. No need to track tension levels between the United States and Japan – the war begins when it begins.

There are no Chinese factions: China is a unitary state, the Chinese Empire, allied to Japan. There’s no diplomacy regarding minor countries: the only ones on the map have already chosen sides (the Netherlands are allied with Britain, Siam and China with Japan).

Co-Prosperity Sphere opens in 1943, with all of the participants having engaged in an arms build-up over the preceding years: everyone is ready to go to war, at least moreso than in the standard scenarios of Great Pacific War. The United States is the aggressor (pretty much a requirement since Japan starts the game controlling so much more of the map), pulling its allies along with it into a Pacific-wide conflict. Japan has its defensive perimeter in place, supported by a powerful fleet, a large army and dynamic economy. But the Americans can cause immense disruption with their series of planned surprise attacks.

There are four scenarios presented in Co-Prosperity Sphere. There’s a first-year scenario, sort of a mirror of the introductory scenario of Great Pacific War but with much more action thanks to those larger fleets and armies. That gives an opportunity to finish a game within a few hours, something many players might appreciate.

Of course it’s not Great Pacific War without the sprawling campaign games; that’s what you really want to play anyway. The 1943 campaign opens in 1943, with the American surprise attack on Pearl Harbor, and ends in 1948. Shorter campaign games open in 1945 and 1947, even though we know that if you play a campaign game at all, it’s going to be the long one, so we loaded that one with lots of fleets and armies and air forces.

The strategic situation is much different than that of Great Pacific War. Japan has her defensive perimeter in place, and no endless war in China to drain her limited resources. The perimeter is backed by a large surface fleet with even more aircraft carriers. The Imperial Japanese Army is larger than in Great Pacific War, with better units. Japan is no pushover.

Neither is the United States; the American player can deploy far more of the fleets, ground troops, Marines and air forces from the very start of the game than is possible in Great Pacific War. The Americans must begin their war of aggression from the very fringes of the Pacific basin, dependent on their toeholds at American Samoa and Dutch Harbor and limited use of Australian and British bases. The Japanese are defending interior lines, and have the force and opportunity to eliminate some of the Allied staging grounds, including Australia and India.

I had several widely-separated goals with Co-Prosperity Sphere. First, I looked at just what would have been necessary for Japan to face the United States on an even footing; I wanted to avoid those inevitable game situations where the Japanese player loses interest after the early-war offensives are done and it’s only a matter of time before the massive power of the United States grinds the Empire into dust.

Second, I wanted to provide more play value – scenarios that played faster, and quite simply more of them from which to choose. To do that, I crafted the background story to not only provide a powerful Japan that could stand up to American power, but to use the magic of deus ex machina to do away with the messy realities of history that required most of the special rules in the standard game.

Finally, I sought a strategic framework for our Long War alternative history naval game line, the one that began with Second World War at Sea: Plan Z. Since we’ll be doing a similarly massive expansion set for the Pacific theater (though it’ll probably be even larger than Plan Z) that fit together pretty logically since I’m using Great Pacific War to plot out the story line in that scenario set.

Co-Prosperity Sphere is just a little expansion set, but it meets my goals and that make me pretty happy. I think it’ll meet yours as well.

Click here to order Co-Prosperity Sphere right now.

Great Pacific Package
      Great Pacific War (Final Edition)
      Co-Prosperity Sphere
Retail Price: $89.98
Package Price: $70
Gold Club Price: $56
You can experience the Great Pacific Package right here.

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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and NASA Journalist in Space finalist, he has published a great many books, games and articles on historical subjects; people are saying that some of them are actually good. He lives in Birmingham, Alabama with his wife and three children. He misses his Iron Dog, Leopold.

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