@Box_of_Rocks @greatninja3
Not that extreme yet. Spain and Portugal have already expanded into the Americas, and are about to wipe out the Inca, Mayan, and Aztec empires around this time period.
For Japan to win WW2, they'd have to build up a large enough population and naval forces strong enough and advanced enough to challenge Dutch control of the Indies, Spanish control of the Philippines, and British control of Malaysia. Using the rough timeline we have, the alternate Japan has a time frame of about 200 years, give or take a few decades to do.
Reason being that Japan's geography gives terrible iron ore, and there's no oi; both of which drove Imperial Japan's expansion and specifically Attack Plan South, which ended up dragging the USA into WW2 in the first place.
That's also assuming that the other European powers don't notice Japan's population stabilizing due to increased food resources and wanting to curtail a potential rising power in the first place. Also, Shizuko's knowledge doesn't seem to encompass weapons, and even with that big book of modern weaponry, that's a lot of resources that Japan just currently doesn't have access to, to develop (iron being terrible quality for starters). The "thousands of times folded" katana was because the iron was shit.