Japanese Archipelago in the context of "Japanese sea lion"

Japan is often divided into regions, each containing one or more of the country's 47 prefectures at large. Sometimes, they are referred to as "blocs" (ブロック, burokku), or "regional blocs" (地域ブロック, chiiki burokku) as opposed to more granular regional divisions. They are not official administrative units, though they have been used by government officials for statistical and other purposes since 1905. They are widely used in, for example, maps, geography textbooks, and weather reports, and many businesses and institutions use their home regions in their names as well, for example Kyushu National Museum, Kinki Nippon Railway, Chūgoku Bank, and Tōhoku University.

One common division groups the prefectures into eight regions. In this arrangement, of the four main islands of Japan, Hokkaidō, Honshu, Shikoku, and Kyūshū, each form their own region, with Kyūshū also including the Satsunan Islands. The largest island, Honshū, is split into five regions. Okinawa Prefecture is usually considered part of Kyūshū, but it is sometimes treated as its own ninth region.

The first island chain is the first string of major Pacific archipelagos out from the East Asian continental mainland coast. It is principally composed of the Kuril Islands, the Japanese archipelago, the Ryukyu Islands, Taiwan (Formosa), the northern Philippines, and Borneo, hence extending all the way from the Kamchatka Peninsula in the northeast to the Malay Peninsula in the southwest. The first island chain forms one of three island chain doctrines within the island chain strategy in the U.S. foreign policy. It is considered a strategic military barrier to accessing the wider Pacific Ocean given the relative shallowness of waters to the west of the first island chain, which has important implications for submarine detection.

Much of the first island chain is roughly situated in waters claimed by the People's Republic of China (PRC). These include the South China Sea, within the disputed nine-dash line, as well as the East China Sea west of the Okinawa Trough.

The Sakishima Islands (Japanese: 先島諸島 / 先島群島, Hepburn: Sakishima-shotō / Sakishima-guntō; Okinawan: Sachishima; Miyako: Saksїzїma; Yaeyama: Sakїzїma; Yonaguni: Satichima) are an archipelago located at the southernmost end of the Japanese Archipelago. They are part of the Ryukyu Islands and include the Miyako Islands and the Yaeyama Islands. The islands are administered as part of Okinawa Prefecture, Japan.