If you Build 5 Infantry and 5 Tanks, all of your starting money, they only win 75% of the time. Add in the Infantry from Central US as well and it drops to about 60%.
Not sure where you’re getting your numbers, but against a defeding force of 6 inf, 5 arm, 2 ftr, 1 bmr, 1 aa Japan is only about 38% to take the territory, not 60%. The US can make these odds even worse by sending in the EUS fighter, but let’s suppose they send it to Britain.
If Japan simply takes Canada, they will be… slaughtered by an Infantry/Tank force
Correct. So what can Japan hope to accomplish by doing this?
Whereupon Italy takes Western US instead
Nope, cause the Italian fleet is dead the moment it sets foot out of the Med. On UK1, they buy 3 bmr, 2 inf. If Italy moves their fleet as you describe, Britain pounds it with 4 bmr, 3 ftr (1 ftr from FWA, escaping from Egypt on UK1), winning easily with no fighter loses.
If Britain builds a navy on B2 to block Germany while sinking the Italian force, Germany simply destroys the blocking fleet and invades Britain
Uh, not quite. With the 1 IPC saved from UK1, they have 44 to spend UK2 thanks to the Axis opting not to attack british holdings in Africa, Asia, or the Pacific. They buy 2 cv, 2 dd and place them in sz6, along with the dd and fighters already on board. The US adds its dd and fighter on US2 for a grand total of 2 cv, 4 dd, 4 ftr.
So G3 comes along and, if we’re extremely generous and suppose Germany’s entire airforce is intact and in range of sz6, they have 1 ss, 1 ca, 1 cv, 4 ftr, 1 bmr to attack with according to your builds. That gives them at best 20% to clear sz6 for the invasion force. If they choose not to attack, we all know what will happen on UK3…