Saiun-in, Buddhist temple in Sakyō-ku, Kyoto, Japan

Saiun-in is a Jodo-sect tatchu sub-temple of the Konkai Komyo-ji head temple, in Kurodani, Sakyō-ku, Kyoto, with the mountain name Shiun-zan and Amida Nyorai as its main image. Its grounds hold a main hall, a kuri, a mountain gate and an east gate, plus the Shiun-seki hall, which enshrines the stone the monk Honen is said to have sat on in 1175. A statue of Matsudaira Katamori stands on the grounds.

Saiun-in was founded on 8 April 1616 by Sōgon, a Korean-born monk brought to Japan during the Bunroku-Keichō campaigns who later took vows. The 27th abbot of Konkai Kōmyō-ji, Kuyo Ryoteki, gave him the Shiuenseki, a stone kept at that temple on which Hōnen was said to have sat in 1175. Sōgon's continuous nembutsu recitation drew many monks and donations, and the thousand-day rite he began was extended to roughly 100 days of cycles, earning the temple the name Man'nichi-ji.

The temple is also known as Shiuen-ji after the Shiuen-seki, the stone kept in the Shiuen-seki-dō hall, said to be the rock on which Hōnen sat in 1175; its plaque was brushed by Shōkō-in Dōkō. Each June a memorial service for the 352 Aizu domain retainers buried here invites the head of the Aizu Matsudaira family.

Saiun-in stands at 121 Kurodani-chō in Sakyō-ku, a short walk from the Kurodani area of the Kōmyō-ji precinct on the slopes of Higashiyama. The nearest station, Jingū-Marutamachi on the Keihan Ōtō line, is about 32 minutes away on foot. The grounds hold the main hall, the kuri, the east gate, the mountain gate and the Shiuun-seki hall, with the graves of 352 Aizu retainers behind.

The temple is commonly known as Shium-seki, after the stone on which Hōnen is said to have sat in 1175; it is kept in the Shium-seki Hall, rebuilt by Sōshin in 1680. The hall's plaque was brushed by Shōkō-in Dōkō. The temple also holds the graves of 352 Aizu retainers, and a memorial service is held each June with the head of the Aizu-Matsudaira family invited.