High Quality Content by WIKIPEDIA articles! Saikai is a city located in Nagasaki, Japan. Saikai City was formed through the merger of five towns on the northern tip of Nishisonogi Peninsula on April 1, 2005: the former town of Saikai, seto, shima, Sakito and Seihi, all from Nishisonogi District. Its city hall is the former town hall of seto. The economy of the towns in this area were dominated by fishing and whaling in the Edo period, and coal mining in the Meiji period. The area is now primarily agricultural, with forestry products and tourism also of importance.