Kosai (Japanese: 湖西市) is a city in Shizuoka, Japan.
Arai Sekisho and Hatago-Kinokuniya Archives (新井関所), Arai-chō Hamana-gun Arai 1227-5 (across the lake from Bentenjima), 34.6947°, 137.5613°, +81 53 594-3615. Tu-Su 09:00-16:30. This important travel checkpoint on the Tokaido highway was established in 1600 by Ieyasu Tokugawa, and is the only surviving original building of such a checkpoint. The checkpoint enforced strict regulations to keep guns out of Totomi precinct, and to keep women in. The archives hall next door contains old checkpoint records. Adults ¥300, children ¥100, add ¥100/50 to enter the archives as well
Honkō-ji Temple (本興寺), Washizu 384 - Kosai-shi (across the lake from Bentenjima), 34.717167°, 137.538194°, +81 53 576-0054. The main hall is designated as a National Important Cultural Property. There is also a park here, a nice place to picnic. ¥300, children ¥200
2nd-order administrative division
Primary administrative division