was a feudal domain under the Tokugawa shogunate of Edo period Japan. The domain was centered at KÃ Âfu Castle what is now the city of KÃ Âfu, Yamanashi.
Kai Province was initially entrusted to important Tokugawa clan members as Kà Âfu Domain, and later to the highly placed fudai daimyà  Yanagisawa clan, with periods of direct shogunal rule ( tenryà  ) in between. Following the transfer of Yanagisawa Yoshisato to Yamato Province in 1724, the domain remained under direct shogunal control until the Meiji Restoration.
With the abolition of the han system in July 1871, Kà Âfu Domain became âÂÂKà Âfu PrefectureâÂÂ, which subsequently was renamed Yamanashi Prefecture.