The not-necessarily-so assumption used in most of the scenarios: China invades Taiwan to force unification with the self-governed island, and the US decides to intervene heavily with its military. Also assumed but far from certain: Japan grants expanded rights to use US bases located on its territory, while stopping short of intervening directly unless Japanese land is attacked. Nuclear weapons aren’t used in the scenarios, and the weapons available are based on capabilities the nations have demonstrated or have concrete plans to deploy by 2026.

China’s test-firing of missiles in recent days in response to US House Speaker Nancy Pelosi’s visit to Taiwan underscored a Chinese capability that’s already assumed in the gameplay.

In 18 of the 22 rounds of the game played to this point, Chinese missiles sink a large part of the US and Japanese surface fleet and destroy “hundreds of aircraft on the ground,” according to Cancian, a former White House defense budget analyst and retired US Marine. “However, allied air and naval counterattacks hammer the exposed Chinese amphibious and surface fleet, eventually sinking about 150 ships.”