I read it in the late 90s, so it was written before then.  The person that lent the book to me called it a ‘cult classic’.  If I had to guess, I would estimate that it written in late 1960s.
I seem to recall that it involved a Japanese samurai, but he could have been a giant.  It also could have been from China.  They were a stowaway and travelled to USA.  I believe it was San Francisco.  It may have hidden in steamer trunk.
This was not YA.  More of a fantastical book for adults with nice meaning.
I’ve been wondering about this book for about twenty years.