of Sakuoka was merged into the town of Tsukuba. July 1, 1957 - The village of Sugama was merged into the town of Tsukuba. (4 towns, 2 villages) April 1, 1985 - The village of Ina was elevated to town status. (5 towns, 1 village) November 30, 1987 - The towns of Yatabe, Toyosato and Oho merged with the village of Sakura (from Niihari District) to form the city of Tsukuba. (2 towns, 1 village) January 31, 1988 - The town of Tsukuba was merged into the city of Tsukuba. (1 town, 1 village) March 27, 2006 - The town of Ina and the village of Yawara were merged to create the city of Tsukubamirai. Therefore, Tsukuba District was dissolved as a result of this merger. Former districts of Ibaraki Prefecture