Hoon-in (pronounced ho-on-in) is a small sub-temple located along the long road which leads to Sennyu-ji. The road is bordered by trees (rare in Kyoto!) and make for a pleasant stroll when the sun is hitting hard. This little temple is not visitable per-se, but you can have a quick look around if you wish; the grounds are open. I have heard of a special visit some years ago but as far as I can remember it was more for showing statues and other relics rather than to show off a beautiful garden. Sennyu-ji and (especially) Unryu-in are much much much more interesting, so you can safely pass this one unless you really want to put an "I was here" pin on your map.
Nearby: Imakumano Kannon-ji 今熊野観音寺 (350m), Shōrin-ji 勝林寺 (360m), Raigō-in 来迎院 (370m), Kaizan-dō 開山堂 (460m), Ryōgin-an 龍吟庵 (460m), Sokushū-in 即宗院 (460m), Shōkō-in 盛光院 (460m), Unryū-in 雲龍院 (500m), Ikkai-in 一華院 (560m), Tōfuku-ji 東福寺 (600m),...
External links: 京都風光, Satellite view, Map
Keywords: Japan, 日本, Japon, Kyoto, 京都, 東山, Higashiyama, Senyu-ji, 泉涌寺, temple, 寺院, 仏閣, 法音院, Hōon-in, subtemple, 塔頭