The Fillmore was a long-time Japanese district until WWII changed everything. Blacks brought in from the south for labor to build ships, etc., needed housing
well a bunch of empty homes and apartments vacated by Japanese-Americans were available. Most Japanese-Americans returning from camps after WWII didn't like the new neighborhood mix and went elsewhere. The ones who returned to their former residences (taken care of by friendly whites) put up a barrier at Geary and Fillmore to separate themselves from the black ghetto, in the form of a Japanese mall and hotel complex; very effective. My dentist (who was a former internee at a camp) is one block from that Chinese consulate, so I pass by there often. Lots of demonstrations there by religious Chinese against the red Chinese government.