His sister, who married into Shoka (mercantile house) in Osaka recommended him to Shinsengumi, which caused Shinpachi NAGAKURA to refer that Kawai was from Osaka.
新選組には、大阪で商家に嫁いでいた妹が推薦（このため、永倉新八が河合の事を大阪市の出身と後に記す原因となった）。