Wakaenoshima is an artificial island located in the eastern part of Sagami Bay. It was built in 1232 when Hojo Yasutoki was serving as the regent.​ The oldest harbor still existing today on an artificial island was built in 1232, when Hojo Yasutoki was regent. The island is located in the east of Sagami Bay and is part of Zaimoku-za, one of the seven districts of Kamakura, collectively known as Shichi-za: Zaimoku-za (lumber), Kome-za (rice), Aimono-za (dried seafood), Bakuro-za (cattle or horse), Sumi-za (charcoal), Kinu-za (silk), and Sendatsumi-za. At low tide, megalithic cairns can be seen about 200 metres west of the tip of the cape, a reminder of the old days when ships docked here for the timber trade.