In the 1960's and 70's Sadao Yairi, made guitars under the S. Yairi name. H. (Hiroshi) Yairi is Sadao Yairi's son, and made acoustic guitars under his supervision (and usually signed and/or stamped by S. Yairi). Sadao was Kazuo's uncle, and the brother of Giichi Yairi (Kazuo's father).
S. and H. Yairi are marketed under a few names in the US: Yairi & Sons, Kohno, Shelly, and Wilson are some of the names.
Yairi is now the name of the top line of Alvarez guitars. Alvarez Yairi guitars are hand-made in the same factory as K. (Kazuo) Yairi guitars and are only sold under the Alvarez name in the United States.