My grandfather was called Gansui Ishikawa. He came alone to Brazil from Japan in 1921. There was no other person from Japan coming to Brazil with the same name, at least in São Paulo State. His brother came after some years, but died single, so, every Ishikawa that can be a relative of mine in Brazil is in the tree started by Gansui.
I don’t know the name of any other relative he had in Japan, and… perhaps, you were searching for him and we can start a new family link