The Japanese word irezumi refers to the insertion of ink under the skin to leave a permanent, usually decorative mark, in other words, tattooing. Tattooing in Japan dates back to 10000 BC and was done for Spiritual reasons. To decorate the body and for ritual and status. In the Kofun period (300-600 AD) tattoos began to be placed on criminals as a punishment and often used character art to symbolize the crime the offender committed. Still today in Japan, tattoos are associated with criminality with the yakuza, Japan's version of the mafia. Many businesses in Japan still ban customers with tattoos.
Some common images in traditional Japanese tattoos include mythological beasts, monsters and animals such as Dragons, Kirin, Foo Dogs, Koi Fish, Tigers, Snakes with elaborate backgrounds of waves, bamboo and flowers.
Here are a few examples of Japanese style tattoos by American
Jason Brooks of Rock of Ages Tattoo - Austin, TXHere is a Yakuza member's "Irezumi" showing a fierce tiger (photo by Sean Wilson)

Below is a Fu Lion (from
Ed and Julie Nelson's Home Page)
(note: you can see more of Ed's work on his homepage, he has quite a bit of Japanese style ink)
My first tattoo was a Chinese Lucky Dragon very similar to the one on Ed's page except mine is a band around my right arm with the Dragon biting his own tail.