(also spelled 入墨 or sometimes 刺青) is the Japanese word for tattoo, and is used in English to refer to a distinctive style of Japanese tattooing, though it is also used as a blanket term to describe a number of tattoo styles originating in Japan, including tattooing traditions from both the Ainu people and the Ryukyuan Kingdom. All forms of irezumi are applied by hand, using wooden handles and metal needles attached via silk thread. This method also requires special ink known as Nara ink (also called zumi); tattooing practiced by both the Ainu people and the Ryukyuan people uses ink derived from the indigo plant. It is a painful and time-consuming process, practiced by a limited number of specialists known as horishi. Horishi typically have one or more apprentices working for them, whose apprenticeship can last for a long time period; historically, horishi were admired as figures of bravery and roguish sex appeal. During the Edo period, irezumi kei ("tattoo punishment") was a criminal penalty. The location of the tattoo was determined by the crime; thieves were tattooed on the arm, murderers on the head. The shape of the tattoo was based on where the crime occurred. Tattoos came to be associated with criminals within Japanese society. Two characters in the 1972 film Hanzo the Razor, set in the Edo period, are depicted with ring tattoos on their left arms as punishment for theft and kidnapping. At the beginning of the Meiji period, the Japanese government outlawed tattoos, which reinforced the stigma against people with tattoos and tattooing in modern-day Japan. In Japanese, irezumi literally means 'inserting ink' and can be written in several ways, most commonly as 入れ墨. Synonyms include patterning the body, piercing with blue, and tattooing. Each of these synonyms can also be read as irezumi, a reading of these kanji. Tattoos are also sometimes called carving which have a slightly different significance. Tattooing for spiritual and decorative purposes in Japan is thought to extend back to at least the Jōmon or paleolithic period (approximately 10,000 BC) on the Japanese archipelago.