Also, the Japanese government points out that "the Treaty of Shimonoseki does not clearly define the geographical limits of the island of Formosa and the islands appertaining or belonging to Formosa ceded to Japan by the Qing Dynasty of China, nothing in the negotiation history (or otherwise) supports the interpretation that the Senkaku Islands are included in the island of Formosa and the islands appertaining or belonging to it in Article 2b of the Treaty," and had "incorporated the Senkaku Islands into Okinawa Prefecture before the treaty was signed." In 1972, the United States ended its occupation of Okinawa and the Ryukyu Island chain, which included the Senkaku Islands.