I came across this posted on the PMJS list, and it looked interesting:
"....I have come across an
interesting comment on descendants of the Keicho mission in Spain while
I was reading through the Nihonshi thread concerning the film The Last
Samurai on the notorious 2ch site.
It seems that Hasekura Tsunenaga and other Japanese left offspring in
Spain while they were there. In a town in Andalucia called Coria del
Rio where the Keicho mission arrived, many people bear the surname
"Japon" from the Spanish word for Japan. They claim that they are the
descendants of samurai. Their children have a clear Mongolian spot
(MOKOHAN) which no Spanish children have. In a park in the town, there
is a statue of Hasekura in haori, hakama, with two swords.