The name "Otaru" is of
Ainu origin, possibly meaning "River running through the sandy beach". The very small remaining part of the Temiya Cave contains carvings from the Zoku-Jōmon period of Ainu history, around A.D. 400. Mount Akaiwa (Northwest part of Otaru) is memorialized in the Ainu tradition in the story of
Sitonai, village chief's teenage daughter who had slain a white snake from the mountain's cave that demanded sacrifices of girls every year. The legend explains the name of a big cave on Mount Akaiwa, Hakuryu Gongen Cave (, "White Dragon
Gongen Cave") and the reason why a shrine was built on the mountain (to protect the village from being haunted by the snake). The city flourished well as the financial and business center in Hokkaido as well as the trade port with Japanese ruled southern Sakhalin until the 1920s. Otaru was redesignated as a city on August 1, 1922. On December 27, 1924, a freight train loaded with 600 cases of dynamite, unloaded from the freighter
Shoho Maru, exploded in Temiya Station, killing 94 people and injuring 200 more, in addition to damaging the warehouse, the harbour facilities, and the surrounding area. During
World War II, Otaru housed a prison camp for
Aleuts. They were forcefully taken there following the
Japanese occupation of Attu, which is part of
Alaska's
Aleutian Islands chain in the Northern Pacific. Nearly half of the Aleuts at the camp died from starvation or the spread of illnesses such as
tuberculosis, while their children there were forced to learn
Japanese. During the closing stages of the war, Otaru was
bombed by American naval aircraft in July 1945. Since the 1950s, as the coal industry around the city went into a decline, the status of the economic hub shifted from Otaru to Sapporo. File:Otaruharbour-1876.png|Otaru in 1876 File:Otaru City in Hokkaido 1909 Meiji 42.png|Otaru in 1909 File:Otaru Port in Hokkaido 1909 Meiji 42.png|Otaru port in 1909 File:130823 Bank of Japan Otaru Museum02s4.jpg|Former
Bank of Japan Otaru Branch, now home to the Otaru Museum == Geography ==