Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Yahatahigashi-ku is a ward of Kitaky sh , Fukuoka, Japan. It is the second smallest ward in Kitaky sh after Tobata ward at only 36.36 square kilometres. Residents have a very high average age, one of the highest in Japan. The population was 77,077 at the end of September 2003. The ward contains the Space World amusement park, which is popular with tour groups, especially from Taiwan and Korea. It also contains the Kawachi Reservoir, built to provide cooling water for the Yahata steelworks in the 1920s. When the dam was built it was the largest in Asia. An onsen (hot spring) facility, Ajisai no Yu, has recently been built and includes outdoor bathing (rotenburo).