Why did the Japanese start a program of imperialism?
Imperialism is extending one’s country over others. Said another way, it is collecting countries. Japan wanted all of the countries in Asia, so it would have all of the raw material in asia. It also wanted Russia, as it was closer to Japan than South East Asia. But after fighting Russia twice, once in 1904-1905, then again in 1939, they had had enough of fighting Russia.