Hey Akana, so San Francisco is about 1.47% Japanese (11,500 people) that means you will definitely find other Japanese people but for the most part Chinese (19.97%) make up the biggest Asian group. There is a pretty sizable JapanTown and Japanese food is pretty popular (ramen, sushi, curry,etc) so you won't have trouble finding food that reminds you of home. You might look into the Japan society of Northern California, Japanese cultural and community center and the Japanese American association of Northern California as a way to network and find other Japanese Americans and immigrants. I will say ( as a bit of a disclaimer) being an LA transplant to the SF Bay Area that I think the Japanese community in Los Angeles is larger and more active. がんばろう