Name of a japanese character?

i recently read a book about a young man from japan during the feudal period of (the 1800s). He started out as a fisherman at the age of nine. Then, he and his co-fishermen were shipwrecked. mon-jirro? maybe. Anyway, they were saved by american whalers, but knew that they wouldn't be allowed back into Japan. They were taken to hawaii, and the boy was adopted by the captain, and sent to school in america. He went prospecting for gold, and found enough to get page back to japan. When he got there(or to an island near there) he was arrested for tresping, but a lord(you know, king-thing?) set him free, and allowed him to see his family again? Eventually, commodore something landed on japanese soil, and negotiated the treaty of Kanagawa. Does anyone(maybe someone who's japanese and is familiar with the story) know the young man's name? Oh, also, he was turned from a fisherman into a samurai(something unknown at the time)