観音院, Buddhist temple in Okaya, Japan

Kannon-in is a Buddhist temple in Okaya with traditional wooden buildings arranged around a central courtyard surrounded by mountains. The complex contains multiple prayer halls and communal spaces designed for both worship and quiet reflection throughout the day.

Kannon-in began as a shrine-temple (shabō) of Suwa Taisha and became a prayer site of the Suwa clan in the medieval period. It was revived with Suwa Tadatsune, lord of Suwa, as founder, and the main hall was rebuilt in 1715 by Suwa Tadatora. In 1963 a memorial tower for Suwa Goryōnin was erected on the elevated grounds.

The temple is commonly called Kosaka Kannon-in, after its location in the Kosaka area of Minato, Okaya. Its main image is an Eleven-Faced Kannon. In Inoue Yasushi's novel Fūrin Kazan, Princess Yufu, daughter of Suwa Yorishige and mother of Takeda Katsuyori, is portrayed as living at this temple, and the 2007 NHK taiga drama of the same name also features it.

The temple grounds are accessible by public transportation from central Okaya and can be explored freely during daylight hours. Wear comfortable shoes as the site spans multiple levels with some uneven pathways typical of traditional temple settings.

In Inoue Yasushi's novel Fūrin Kazan, Suwa Yorishige's daughter Yufu-hime (Suwa Goryōnin) is portrayed as living at this temple after bearing Takeda Katsuyori; the 2007 NHK taiga drama based on the novel also features Kannon-in. A memorial tower to Suwa Goryōnin was built on the temple's elevated grounds in 1963.