Irezumi (刺青) means tattoo in Japanese and has existed since the Edo era (around 400 years ago).
There are additional Japanese words with similar meaning such as: Horimono, Shisei, Monmon, Gaman, however Irezumi is most commonly used. The literal translation of Irezumi is 刺 poke 青 blue. Traditional Japanese Sumi ink turns a beautiful blue-black color after the ink goes into the skin.
Irezumi can be found in two forms 2 of Kanji (logographic Japanese writing style) 刺青 (poke blue) and 入れ墨, which means punishment for crime.
There are several reasons as to why the Japanese started make Irezumi.One of the reasons is:
During a time when the much of the Japanese public were frustrated with the Daimyo's (government) tyrannical administration, a character called Kuniyoshi Utagawa developed the Ukiyo-e series "水滸伝百八人之一個 108 Heroes of Suikoden". The series consisted of 108 tough guys with tattoos of Japanese motifs, who gathered at Ryozanpaku (Dojo home to elite fighters who specialize in different styles of martial arts) to ridicule and dismiss corrupt officials.
The series became popular among the people, and in turn Irezumi became popular for the purpose of decorating the body, especially among trained by manual workers, mainly firemen.