Since Japan start with only 3 trannies, and have a lot of islands to capture, the Japanese purchasing strategy will most likely be as followed:
T1: Spend 26 IPC: Buy 2 trannies and 2 subs, or 3 trannies and save 5 IPC.
Japan must take control of FIC in T1, and this is similar to what happened in the real war too. FIC was taken by Japan in septembre 1940, more than a year before the Pearl-attack in decembre 1941.
T2: Spend 30 IPC: (Lets assume FIC and two Chines territories was taken in previous turn.) Now we buy two trannies and two destroyers. We need the destroyers because of the US subs out of Alaska that soon will threaten our convoy zones. Now we got a total of 6 trannies, but are that enough to make a successful attack ?
Japan must attack in T2 or T3. In the real war, Japan straifed Hawaii, and attacked Kwangtung (Hong Kong) at the same time. Later attacks in the same “turn” was Phillipines, Malaya, East Indies and Guam/Wake. A T3 attack will have 6 trannies in position for East Indies attacks, and two new trannies from Japan bound for Phillipines. The allies will also be stronger, and UK might get two NO’s.
Anyway, both Kwangtung and Malaya will be captured in the first turn of attacks, and in next turn they could use some factories. So what will it be ? A major in Kwa or a major in Malaya, or a combination of minors ?