The Japan Trench is an oceanic trench, a part of the Pacific Ring of Fire, in the floor of the northern Pacific Ocean off northeast Japan. It extends from the Kuril Islands to the Bonin Islands and is 9,000 m (30,000 ft) at its deepest. It is an extension of the Kuril-Kamchatka Trench to the north and the Izu-Ogasawara Trench to its south. This trench is created when the oceanic Pacific plate subducts beneath the continental Eurasian plate. The subduction process, together with the friction created 'drags' the plates downwards, causing a deep-sea trench to be formed. The Japan Trench is one of the causes of the tsunamis and earthquakes in Japan.
In October 2008, a UK-Japan team discovered a shoal of fish, Pseudoliparis amblystomopsis at a depth of 7.7km (4.8 miles) in the trench, these are believed to be the deepest living fish ever recorded.