Kōanji, Buddhist temple in Fuchū, Japan

Kōanji is a Zen Buddhist temple in Fuchū featuring a main hall built in 1803 and a bell tower from 1856, both reflecting the architectural style of the Sōtō school. The layout and design of these structures emphasize the straightforward, functional approach characteristic of this Buddhist tradition.

The temple began as a residence of Fujiwara no Hidesato, later converted into Jōshō-ji. In the Nanboku-chō period, around 1340, Ashikaga Takauji had it rebuilt as a Rinzai Zen temple and designated it one of the Ankoku-ji, naming it Kōan-ji after his former name, Takauji. It later became a Sōtō temple in the early Edo period.

The name Kōanji comes from Ashikaga Takauji's former personal name, Takauji (高氏), when he renamed the temple Ryūmonzan Kōan Gokokuzenji in the Kōei era around 1340. The main hall's plaque reads "Tōji-in", the posthumous Buddhist name of Takauji, the temple's founder. The grounds keep traces of the earlier Jōsei-ji, including the story that Musashibō Benkei copied the Daihannyakyō here for Minamoto no Yoshitsune.

Kōanji stands at 2-4-1 Katamachi, Fuchū, about seven minutes on foot from Bubaigawara Station on the Keio and JR Nambu lines. The main hall, bell tower and mountain gate with its two Niō statues are all within the compact precinct, so the grounds can be seen in a short visit.

The temple's main hall carries a plaque reading "Tōji-in", the posthumous Buddhist name of founder Ashikaga Takauji. The 1872 gate with its two Niō guardian statues, the 1856 bell tower and the 1803 main hall are all listed as Tokyo Metropolitan Selected Historical Buildings.