oh one thing interesting about Japanese history that you can find English sources on was that it had like no good transit routes, it was so steep you had the southern coastal waters where currents/winds would sweep you out into the middle of the Pacific

and the northern waters which were practically arctic tho they at least connected to China & Korea enough for some fun piracy

and Lake Biwa in the middle which was like the Great Lakes for being an industrial center but maybe more like the African Great Lakes for not having a useful outlet

past that it was like footpaths ‘cause until Hokkaido (which was the Canada [or Ireland] to Japan’s England SURPRISINGLY RECENTLY) it’s not like anyone had plains to fodder traction animals outside Kanto anyway