He makes mainly Guitars including some very impressive Harp Guitars, but over the years he has made some Ukuleles too. He started out in the 1970's working in one of the Japanese instrument factories and decided to start up on his own in 1991 when he opened a workshop in Takato, Nagano prefecture. Apparently in 2006 his order books were full until 2016.
From Honolulu, Hawaii, Greg Uyehara uses the brand name GKU and specializes in spruce top Tenor Ukuleles with optional cutaways, (he does use other woods and make other sizes sometimes though).