The Yakuza is an organized crime network of Japanese origin which is worldwide.
The word "Yakuza" comes from Sammai Karuta, a Japanese gambling game. In which getting 19 points is the ideal. If you drew the number 20 which was Eight (Ya), Nine (Ku), and Three (Za), it was called "good for nothing".
The Yakuza has spread globally as successfully as the Japanese corporations. In the Yakuza there are only two paths, death or prison. They are among the most violent of all organized crime groups and possibly the most widespread. It has a larger membership than the Mafia. They are based in the Osaka region back in Japan. Due to extensive infiltration of the local police in Japan by the Yakuza, the National Police Agency (Japan's FBI) has been unable to crack the Yakuza. Which is made worse by the pressure placed on the overworked police by the Yakuza-influenced Osaka corporations.
It is involved in a wide variety of criminal activities, from smuggling to gambling, the drug trade to prostitution, and so on. Unlike the Triads who invest a large part of their profits back into the community, the Yakuza like the Sudams and some of the Mafia organizations shows no concern for its community and is concerned only about making money.
The leader of a Yakuza clan is called the Oyabun who has his powers personally granted by the chiefs of the Osaka Clan. The chiefs are a loose alliance of Yakuza bosses overseeing the worldwide Yakuza operations, who on occasion will war with each other. Every Yakuza clan consists of a number of gangs who are led by captains who have been appointed by the Oyabun. These captains in turn appoint lieutenants to supervise a specific area of gang activity. The captains are required to regularly pay tribute to the Oyabun, who in turn pays tribute to the Osaka Clan chiefs.
Yakuza recruit from the Bosozuka, the hot rod and motorcycle gangs of Japan. Which are bloodthirsty gangs used by the Yakuza clans for indirect intimidation. The Yakuza also run orphanages (mostly in Japan), from which they recruit over 50% of their young Yaks.
Yakuza go into extensive body tattoing, which is used to identify what clan they are affiliated with. Body tattoing is seen by the Yakuza, like the street gangs see their "Colors". Though they don't publicly display them, the Yakuza are proud of their tattoos.
Failure is not accepted among the Yakuza and if one fails, a digit (piece of a finger) must be removed in a ritual called the Yubitsume. Among the Yakuza, they are exceptionally courteous and the smallest breach in conduct results in either Yubitsume or a mob war. They are big on gift-giving and Yakuza that are visiting always pay tribute to the clan or gang chiefs.
In reality, the Japanese Yakuza has always been a pretty insular organization and has only dominated the underworld of Japan, not other countries. China has always been the turf of the Chinese Triads and other similar outfits. In Southeast Asia, it's the Chinese Triads (and before them Chinese pirates) who have been at the top of the criminal pecking order since the 1700s. Never have the Yakuza earned more money than the Chinese Triads nor have they had a tenth of its manpower.
When the Yakuza has expanded outwards of Japan, first during World War Two and later again in the 1970s-90s it was not to conquer new territories or rackets but to establish operations to bring product to Japan and to provide vices for overseas Japanese. They ran gambling and prostitution rackets whose sole clientele were Japanese soldiers and later Japanese tourists and corporate expatriats. Methamphetamines, firearms, and women were sent back to Japan. This was the same everywhere from Korea during World War 2 to the Philippines, Thailand, Hawaii, and California in the booming 1980s-90s.
PASS, G. "Protect & Serve Sourcebook". 1st ed. Berkeley CA: R. Talsorian Games, 1992
PASQUARETTE, C. "Pacific Rim Sourcebook". 1st ed. Berkeley CA: R. Talsorian Games, 1994
QUINTANAR, D. "Eurosource Plus Sourcebook:. 1st ed. Berkeley CA: R. Talsorian Games, 1995