The Japanese government, which sought to emulate the empires of Europe in their tradition of enforcing so-called Unequal Treaties, responded by sending the Japanese gunboat "Unyō" towards Busan and another warship to the Bay of Yeongheung on the pretext of surveying sea routes, meaning to pressure Korea into opening its doors. The "Unyō" ventured into restricted waters off Ganghwa Island, provoking an attack from Korean shore batteries. The "Unyō" fled but the Japanese used the incident as a pretext to force a treaty on the Korean government. In 1876 six naval vessels and an imperial Japanese envoy were sent to Ganghwa Island to enforce this command.