 The US-Japan Security Treaty (ANPO) signed in 1952 provides for the continuation of the American military presence in Japan, and the United States continues to maintain a heavy military presence on Okinawa Island.This set the stage for renewed political activism for Ryukyuan independence.The Ryukyu independence movement claims both the 1609 invasion by Satsuma Domain and the Meiji construction of the Okinawa prefecture as colonial annexations of the Ryukyu Kingdom.