The Final Countdown: Isolating Japan
The Allies can also use creative carrier tactics to isolate Japan. In the right conditions, this can paralyze most or even all Japanese units. The possibility of such tactics is a good reason for Japan to maintain air units in Japan and Okinawa at all times, as well as some garrison in Pusan. When such assets are no longer available, such as in the end game, isolating units outside the Home Islands from in-supply HQs can become a frequent occurrence with high logistic Allied cards.
Here is an example of how the Allies can employ such tactics. It is late 1944, and the Allies objective for the next operation is to take Iwo Jima (for the B-29 benefits, securing an air base in range of the Home Islands, and taking a location to make Progress of War) and to isolate Saipan. The Allies only have 1 ASP for this operation, and thus can’t risk a reaction AA invasion to the Iwo Jima invasion; but they do have a good card, which permits activating 9 units with the relevant HQ, although the allies are under ISR. Moreover, the Allies want to maximize Japanese Air/Naval losses while minimizing Allied losses, so sending ships in "penny packets" to smother all available reaction-invasion stacks is not attractive. Finally, as it is late in the game, Japan has two HQs in Japan; South HQ is still in Saigon, and the Allies have an unbroken chain of un-netralized AZOIs from Ulithi south to Australia.
The Allies’ dilemma is how to achieve objectives without having to soak off the potential reaction forces in Manila, Taiwan, Shangai, and Soeul with valuable ships? The Answer: Use carriers to isolate Japan from the available reaction forces and defeat those forces in detail.
Specifically, the Allies use their 9 activations to activate 7 carrier units, a BB, and a Marine XX (which uses 1 ASP to invade Iwo Jima). The carriers move to into positions such that Japanese forces in Okinawa, Korea, and points West are out of supply. The units are out of supply because (i) Allied CVs block the tracing of supply in the hexes they exclusively occupy; and (ii) the CVs exert un-neutralized AZOIs in the hexes indicated by the “Critical AZOI” markers below. The net effect is a wall of ships and unneutralized AZOIs that cut off South HQ is Saigon from the Home Islands, thus preventing that HQ from supply the units circled in Red, as well as cutting off those units from the still in-supply HQs in Japan.
The Allies then declare battle hexes designed to maximize Japanese casualties while still ensuring that Iwo Jima will be taken and Saipan isolated. Absent subs, the single Essex-class CV at Battle D will ensure the Marines can take Iwo Jima, while the 42 A/N factors at minimum +3 DRM at Battle E ensure elimination of the two reduced Japanese air/naval units at Saipan. The remaining battles are necessary so the allied CVs can be stationed to cut-off the potential reaction forces. They should produce few Allied casualties and kill a number of Japanese air/naval steps. The only true “soak off” is Battle A against Kure, where a reduced Allied CVL is at risk.
In reaction, Japan will not be able to activate any of the forces circle in red. The Allies will thus be able to ensure favorable attrition and achieve key objectives. If Japan neglects to place a unit in Pusan and air units in strategic locations with its next play, the Allies may be able to employ this tactic again. A unit in Pusan would make this maneuver harder for the Allies, as only Allied units in hexes otherwise unoccupied by Japan cut supply; merely declaring a battle hex in Pusan would not work, as the below illustrates
If Japan garrisons Pusan, the Allied moves will only place Okinawa out of supply, exposing the attacking Allied forces to possible massed reaction. Japanese units and HQs can trace supply through Pusan, since it is not “enemy occupied” as defined in the game (which means solely enemy occupied). Placing units outside of Japan out of supply is still possible with Pusan garrisoned, but requires Allied CVs operating on the Chinese coast, diverting resources from more productive uses.
Summary
In summary, carrier units in Empire of the Sun have the ability to place enemy air units out of supply, thereby eliminating enemy ZoIs. Such tactics can serve a number of purposes. First, eliminating enemy air ZoIs can facilitate invasions without fear of reaction or special reaction. Second, because of this ability to make "risk free" invasions (or in some circumstances 'bloodless'invasions), judicious use of CVs can be critical to the Allied ability to make Progress of War, especially in Turns 4-6 before the Essex Class CVs arrive and Allied naval assets are scarce. Finally, in the right circumstances, carrier units can be used to sever significant reaction forces from their HQ units, enabling the player on the Offensive achieve attrition without fear of significant reaction. The above illustrates each of these tactics, which can be critical to a successful overall Allied strategy.