Why did the japanese come to america? ?

Japanese immigrants first came to the Pacific Northwest in the 1880s, when federal legislation that excluded further Chinese immigration created demands for new immigrant labor. Railroads in particular recruited Issei –or first generation immigrants--from Hawaii and Japan.
 
For why?
Because they want to learn more about outside world, they don't want to stay in their country like know nothing, when the first boat and gun came to Japan, they were feel so wired about they, they thought everyone still use what they use, do what they do. So they want to change.