Miwa-jinja, Fuefuki, Shinto shrine in Japan

Miwa-jinja is a Shinto shrine in the Ninomiya district of Fuefuki, Yamanashi Prefecture, and the ninomiya (second shrine) of Kai Province. It enshrines Ōmononushi-no-kami and is built in the nagare-zukuri style, with a curved roof extending over the haiden. A wooden standing statue of Ōmononushi from the Heian period is designated an Important Cultural Property.

According to shrine tradition recorded in the Kai Province shrine and temple records, the shrine was founded when the Kai no Kuni no Miyatsuko Shiomi no Sukune invited the deity from Ōmiwa Shrine in Yamato during the reign of Emperor Keikō. Its first documentary mention is an 863 entry in the Nihon Sandai Jitsuroku, when it was granted the fifth rank; it later received the title of Second Shrine (Ninomiya) from Emperor Ichijō. In 1479 it was caught in fighting when the Ōi clan of Saku invaded Kai, and it later received land donations and exemptions from Takeda Shingen.

The shrine's name, Miwa-jinja, comes from the deity Ōmononushi, worshipped at Ōmiwa Shrine in Nara, from which it was ritually transferred. The shrine is the ninomiya (second shrine) of Kai Province, and the district name Ninomiya derives from it. The spring festival features the shrine's own Ōdai Kagura, a 20-piece dance repertoire begun in the Genroku era and revived in 1754.

The shrine stands in the Ninomiya district in the northwest of the former Misaka town area, east of the Kofu basin, with the Oyamada area and its Kami-no-miya, Kinehashi Shrine, further east. The spring festival is held on the first Sunday of April, when the mikoshi is carried to Kinehashi Shrine and the dance continues until it returns. The yudate rite takes place on 8 February.

The shrine keeps the Tenbun Nenjū Ninomiya Saireichō, a 75-page festival register attributed to 1575. It records dates, costs and who bore them for wartime rites, and lists seafood served then, including bonito, sōdagatsuo, sardines and abalone, showing marine products reached inland Kai.