Hakata Bay

Hakata Bay (博多湾, Hakata-wan^?) is a bay in the northwestern part of Fukuoka city, on the Japanese island of Kyūshū. It faces the Tsushima Strait, and features beaches and a port, though parts of the bay have been reclaimed in the expansion of the city of Fukuoka. The bay is perhaps most famous for the Mongol invasions of Japan of 1274 and 1281 which took place nearby; both invasions are sometimes referred to as the "Battle of Hakata Bay."

The Bay is defined by shoal Umi-no-nakamichi and tombolo Shika-no-shima (Shika Island) to the north, and Genkai-jima (Genkai Island) to the northwest, and the Itoshima Peninsula to the west. Five wards of Fukuoka city border on the bay, which is sometimes labeled "Fukuoka Bay" on maps. Sometimes, the bay is divided into Hakata, Fukuoka, and Imazu Bays, though for simplicity's sake, the term "Hakata Bay" is commonly used as a catch-all to refer to all three.

The bay is roughly 10 km from north to south, and 20 km from east to west, covering an area of roughly 133 km². The coastline stretches 128 km. The mouth of the bay is only 7.7 km wide, shielding it to a great extent from the waves of the Strait. The bay is only 10 metres deep on average, 23 m at its deepest point, though the tides bring a two-metre change in the water level. Set routes are used, therefore, through the bay, to protect ships' drafts.

Land reclamation began to be undertaken before the Meiji period, and continued into the post-war period. Since 1945, 1167 square kilometres of land have been reclaimed from the bay, primarily to improve or reinforce the effective functioning of the port. In 1994, an artificial island was begun to be created and called "Island City" (アイランドシティ, Airandoshiti).

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