Yakuza (also known as gokudo) are members of traditional organized crime syndicates in Japan. The term Yakuza comes from a Japanese game, Oicho-Kabu (played with hanafuda or kabufuda cards). The worst hand in the game is a set of eight, nine and three. In traditional Japanese forms of counting, these numbers are called Ya, Ku and Sa, thus the origin of the word yakuza. The yakuza took this name because the Ya-Ku-Za hand requires the most skill (at judging opponents, etc.) and, obviously, the best luck in order to win. The name was also used because it signified bad fortune, presumably for anyone who went up against the group. Despite uncertainty about the single origin of Yakuza organizations, most modern Yakuza derive from two classifications which emerged in the mid-Edo Period: tekiya, those who primarily peddled illicit, stolen or shoddy goods; bakuto, those who were involved in or participated in gambling. During the formation of the yakuza, they adopted the traditional Japanese hierarchical structure of oyabun-kobun where kobun (lit. foster child) owe their allegiance to the oyabun (lit. foster parent). In a much later period, the code of jingi (justice and duty) was developed where loyalty and respect are a way of life. The alleys and streets of Shinjuku are a popular modern Tokyo Yakuza hangout.
Yubitsume, or the cutting of one's finger, is a form of penance or apology. Upon a first offence, the transgressor must cut off the tip of his left little finger and hand the severed portion to his boss. Sometimes an underboss may do this in penance to the oyabun if he wants to spare a member of his own gang from further retaliation. Its origin stems from the traditional way of holding a Japanese sword. The bottom three fingers of each hand are used to grip the sword tightly, with the thumb and index fingers slightly loose. The removal of digits starting with the little finger moving up the hand to the index finger progressively weakens a person's sword grip. The idea is that a person with a weak sword grip then has to rely more on the group for protection—reducing individual action. In recent years, prosthetic fingertips have been developed to disguise this distinctive appearance. Many Yakuza have full-body tattoos. These tattoos, known as irezumi in Japan, are still often "hand-poked," that is, the ink is inserted beneath the skin using non-electrical, hand-made and hand held tools with needles of sharpened bamboo or steel. The procedure is expensive and painful which can take years to complete.