As Cimei is located at the southernmost tip of the Penghu islands, it was known during the early Qing Dynasty as "Nanyu" (South Island) or "Nandayu" (Large South Island). As it was thought to be the largest offshore island south of the Penghu Islands, during the late Qing Dynasty and early Republican Period it reverted to the name "Dayu" (Large Island)". During the Japanese Colonial Period "Dayu" was a "Village" under "Wang-an District". It was not until August 1944 that a separate "Dayu District" was created. On December 11, 1945, it was renamed "Dayu Township"...