Iwo Jima in the context of "Bonin Islands"

The Philippine Sea is a marginal sea of the Western Pacific Ocean east of the Philippine Archipelago and the largest sea in the world, occupying an estimated surface area of 5 million square kilometers (2×10^ sq mi). The Philippine Sea Plate forms the floor of the sea. Its western border is the first island chain to the west, comprising the Ryukyu Islands in the northwest and Taiwan in the west. Its southwestern border comprises the Philippine islands of Luzon, Catanduanes, Samar, Leyte, and Mindanao. Its northern border comprises the Japanese islands of Honshu, Shikoku and Kyūshū. Its eastern border is the second island chain to the east, comprising the Bonin Islands and Iwo Jima in the northeast, the Mariana Islands (including Guam, Saipan, and Tinian) in the due east, and Halmahera, Palau, Yap and Ulithi (of the Caroline Islands) in the southeast. Its southern border is Indonesia's Morotai Island.

The sea has a complex and diverse undersea relief. The floor is formed into a structural basin by a series of geologic faults and fracture zones. Island arcs, which are actually extended ridges protruding above the ocean surface due to plate tectonic activity in the area, enclose the Philippine Sea to the north, east and south. The Philippine archipelago, Ryukyu Islands, and the Marianas are examples. Another prominent feature of the Philippine Sea is the presence of deep sea trenches, among them the Philippine Trench and the Mariana Trench, containing the deepest point on the planet.

Chichijima (父島) is the largest and most populous of the Bonin Islands. Chichijima is about 240 km (150 mi) north of Iwo Jima. 23.5 km (9.1 sq mi) in size, the island is home to about 2,120 people (2021). Connected to the mainland only by a day-long ferry that runs a few times a month, the island is nonetheless organized administratively as the seat of Ogasawara Village in the coterminous Ogasawara Subprefecture of the Tokyo Metropolitan Government. Together with the Volcano and Izu Islands, it makes up Japan's Nanpō Islands.

Some Micronesian tools and carvings have been found elsewhere in the Bonins, but Chichijima was long uninhabited when it was rediscovered. Ignored by the Spanish, Dutch, and Japanese Empires for centuries, it was finally claimed by a passing British captain in 1828 and settled by an international group from the Hawaiian Kingdom two years later, the original nucleus of the Bonin Islanders. Britain subsequently yielded to Japanese claims and colonization of the island, which established two villages at Ōmura (大村) and Ōgimura-Fukurosawa (扇村袋沢村). These were formally incorporated in 1940, just before the civilian population was forcibly evacuated to Honshu in 1944 during the end of World War II.

Ogasawara Subprefecture (小笠原支庁, Ogasawara-shichō) is a subprefecture of the Tokyo Metropolitan Government in Japan. The subprefecture covers the Bonin and Volcano Islands and three isolated islets (the "Ogasawara Archipelago") and is coterminous with the village of Ogasawara. The subprefecture covers 104.41 square kilometers (40.31 sq mi) and has a population of 2,930 in 2023. It maintains a main office on Chichijima and a branch office on Hahajima, the two permanent settlements in the islands. (The SDF base on Iwo Jima is supported separately, although still notionally part of the subprefecture and village's jurisdiction.)

The Volcano Islands (火山列島, Kazan Rettō), also known as Iwo Islands (硫黄列島, Iō Rettō) are a group of three Japanese islands in the Northwestern Pacific Ocean. They lie southwest of the Ogasawara Islands and are administered as part of the Ogasawara, Tokyo Metropolis. The islands are all active volcanoes lying atop the Izu–Bonin–Mariana Arc that stretches south to the Marianas. They have an area of 32.55 square kilometres (12.57 sq mi), and a population of 380. The island of Iwo Jima in the Volcano Islands lies about 1,240 kilometres (670 nmi; 771 mi) southeast of Miyazaki.

The Type 93 13 mm heavy machine gun (Japanese: 九三式十三粍機銃 Kyū-san Shiki Jū-san Mirimētoru Kijū), known to the Imperial Japanese Army as the Type Ho 13 mm AA machine cannon (Japanese: ホ式十三粍高射機関砲 Ho Shiki Jū-san Mirimētoru Kōsha Kikanhō), was a license-built version of the Hotchkiss M1930 machine gun used by the Empire of Japan during the Second Sino-Japanese War and World War II.

Mount Suribachi (摺鉢山, Suribachiyama) is a 169-metre (554 ft)-high hill on the southwest end of Iwo Jima in the northwest Pacific Ocean under the administration of Ogasawara Subprefecture, Tokyo Metropolis, Japan.

The hill's name derives from its shape, resembling a suribachi or grinding bowl. It is also known as "Mount Pipe" (パイプ山, paipu-yama), since the volcanic gas and water vapor that rolls in from the summit, alongside the rest of the island, give the appearance of a smoking pipe when viewed from the sea.

Iōjima (硫黄島村, Iōjima-mura) was a village in the Japanese prefecture of Tokyo. Its administrative area covered the whole island of Iwo Jima (officially Iōtō since 2007), one of the Volcano Islands. It existed from 1923 when the Ogasawara islands were organized into modern municipalities to 1952 when mainland Tokyo returned to Japanese sovereignty and Iwo Jima was put under US military administration. When the island was returned to Japan in 1968 it became part of the village of Ogasawara, Tokyo.

In 1943, the village had a population of 1,018 in 192 households. For a period the population was fewer than 1,200.