Just found out that the Guardian has a small collection of Yakuza pictures. Worth a look if you have the time.

In Japan, organized crime and criminals come under the general heading of Yakuza. According to tradition, the name is derived from the worst possible score in a Japanese card game. It comes from Japan’s counterpart to Black Jack, Oicho- Kabu. The general difference between the cardgames is that in Oicho- Kabu is that a winning total of the cards is 19 instead of 21. As you see, the sum of 8, 9 and 3, is 20, which is over in Oicho-Kabu. In a hand resulting in a score of 20, the worst possible score, a player’s final score would be zero.

Among the losing combinations, the phonetic sound of an 8-9-3 sequence is ya - ku - sa. It’s from there the name, yakuza is derived… without worth to society. This doesn’t mean that they have no use for the society, it means that the members are people that somehow do not fit in the society, in other words societies misfits.

The Yakuza were itinerant gamblers, peddlers, renegade warriors and roving bandits. They served shoguns and municipalities and their legend includes a distinct Robin Hood quality that recently emerged during the recent Kobe Earthquake. The Yamaguchi-gumi Yakuza clan quickly mobilized providing on the scene assistance to Kobe’s earthquake victims long before the national government resolved to act. (Source)