One of the most popular Japanese deities, traditionally regarded as the god of archery and war, in which context he is referred to as yumiya Hachiman or 'bow and arrow Hachiman' and symbolised by bow and arrows, yumidai. Hachiman is worshipped at tens of thousands of bunsha of the Kyoto Iwa-shimizu Hachiman-gu and of the original Usa Hachimangu in Kyushu, which enshrines the legendary fifteenth Emperor and culture hero Ojin (Ojin Tenno), Ojin's wife Himegami and his mother, the warlike empress Jingu. Jingu is credited with invading Korea at the end of the second century. These three together constitute Hachiman, but he is generally thought of simply as the emperor Ojin. The name Hachiman means 'eight flags', or possibly 'eight fields'; the figure eight occurs repeatedly in the myths associated with Hachiman and he is sometimes symbolised by eight flags. One etymology identifies 'hachi-man' as the Sino-Japanese reading of 'ya-wata' or 'ya-hata', the name of a kami who in the sixth century revealed himself in the form of a three year old child to be the soul of Ojin, though the identification of Hachiman with Ojin probably occurred as late as the ninth century. More certainly Usa Hachiman was the first kami to be given the Buddhist title of dai-bosatsu (great bodhisattva) sometime between 765 and 781, and he is also regarded as an incarnation (gongen) of Amida Buddha. It was an oracle allegedly from the Usa Hachiman which suggested in the late 8th century that the Rasputin-like Buddhist monk Dokyo should become emperor in place of the descendants of Amaterasu, but when checked by a court official sent to Kyushu (see Go'o jinja) the oracle was reported to be false, and Dokyo fell from grace. Early in the Heian period the Iwashimizu Hachiman-gu was established to the south-west of Kyoto as a bunsha of Usa for the imperial family to revere its ancestral kami. The Minamoto clan regarded Hachiman as their clan deity and the first shogun Minamoto, Yoritomo, founded the Tsurugaoka Hachiman shrine when he moved the capital to Kamakura. Hachiman is linked with Kasuga and Amaterasu in the sanja takusen oracles. Hachiman can be found iconographically represented both as a male deity of war and as a Buddhist priest.
A Popular Dictionary of Shinto. Brian Bocking.