ready-made tattoo images to customers. The Japanese word irezumi means "insertion of ink" and can mean tattoos using tebori, the traditional Japanese hand method, a Western-style machine or any method of tattooing using insertion of ink. The most common word used for traditional Japanese tattoo designs is horimono. Japanese may use the word tattoo to mean non-Japanese styles of tattooing. British anthropologist Ling Roth in 1900 described four methods of skin marking and suggested they be differentiated under the names "tatu", "moko", "cicatrix", and "keloid". The first is by pricking that leaves the skin smooth as found in places including the Pacific Islands. The second is a tattoo combined with chiseling to leave furrows in the skin as found in places including New Zealand. The third is scarification using a knife or chisel as found in places including West Africa. The fourth and the last is scarification by irritating and re-opening a preexisting wound, and re-scarification to form a raised scar as found in places including Tasmania, Australia, Melanesia, and Central Africa. Types The American Academy of Dermatology distinguishes five types of tattoos: traumatic tattoos that result from injuries, such as asphalt from road injuries or pencil lead; amateur tattoos; professional tattoos, both via traditional methods and modern tattoo machines; cosmetic tattoos, also known as "permanent makeup"; and medical tattoos. Traumatic tattoos A traumatic tattoo occurs when a substance such as asphalt or gunpowder is rubbed into a wound as the result of some kind of accident or trauma. When this involves carbon, dermatologists may call the mark a carbon stain instead of a tattoo. Coal miners could develop characteristic marks owing to coal dust getting into wounds. These are particularly difficult to remove as they tend to be spread across several layers of skin, and scarring or permanent discoloration is almost unavoidable depending on the location. An amalgam tattoo is when amalgam particles are implanted in to the soft tissues of the mouth, usually the gums, during dental filling placement or removal. Another example of such accidental tattoos is the result of a deliberate or accidental stabbing with a pencil or pen, leaving graphite or ink beneath the skin. Identification Forcible tattooing for identification A well-known example is the Nazi practice of forcibly tattooing concentration camp inmates with identification numbers during the Holocaust as part of the Nazis' identification system, beginning in fall 1941. The SS introduced the practice