Kaizen-ji, Buddhist temple in Matsugaya, Japan

Kaizen-ji is a Rinzai Zen temple of the Myoshin-ji school in Matsugaya, Taito ward, Tokyo. It was founded in 1624 in the妻恋 area north of Kanda Myojin and later moved to its present site in Asakusa after the Great Fire of Meireki. The temple, known as "Awa-sama-dera" for its close ties to the Hachisuka family of Tokushima, is one of the four Myoshin-ji temples in Edo.

The temple was founded in 1624, during the early years of the Edo period, as part of the Myoshin-ji branch of Rinzai Buddhism. It has kept its original religious role ever since, without major breaks or changes in purpose.

The temple's name is read Kaizen-ji, and it was one of the four Myoshin-ji branch temples in Edo. Because the Hachisuka family of Tokushima domain, 257,000 koku, used it as a family temple, people called it the Awa-sama temple. The graves of loyalist Umeda Unbin and Fujii Naosuke remain here.

The temple sits in Taito ward and can be reached on foot from several nearby train stations. Anyone entering indoor spaces should remove their shoes at the entrance, as is standard at traditional Japanese religious sites.

The temple's name is written with the character for 'sea', linking it to Daimyōzan Kaizen-ji in Kōya, Ibaraki, the temple said to have been founded by Taira no Masakado and regarded as its source temple. The Edo temple once oversaw more than forty subtemples across the Miura Peninsula and Kai Province.