Japan was peacefully minding its own business until Commodore Perry and his black ships from the USA forced the country to open up in 1854

The USA and the UK then helped agitate inside the country for the overthrow of the Tokugawa Shogunate and the Restoration of the Emperor Meiji, setting Japan on an imperialistic path. (An early example of Western backed régime change)

Imperial Japan set out to be another colonialist, extractive power, on the model of the powers that had forced it open. The existing colonialist power in the Pacific, the USA, didn't like how successful it was at doing this, and choked its supply lines of vital resources, leading to war.

This is not to absolve Japan of its war crimes in the first half of the 20th century, particularly against the Chinese and Koreans. My point is that it all started with the forceful intrusion of the USA into the country and Japan will not fully heal until the USA has been thrown out by a Japan that has properly mended its relations with China and other near neighbours