The Yamaguchi-Gumi which was formed in 1915, is the largest Yakuza Clan in Japan. Its membership is estimated to be at least 50,000. Its members make up 45% of the total of all Yakuza in Japan. This group offers an umbrella organization for small Yakuza families all answering to the Kumicho. This clan is based out of Kobe, while it has territory throughout Japan, to include Tokyo.
The leader of the Clan is called the Kumicho. He is the equivalent of a mafia godfather. There are key differences between the mafia godfather and the Kumicho. The Kumicho of the Yamaguchi – Gumi to include the current one is the 6th since 1915. This stability speaks in part to the level of discipline of the clan. While the Mafia in the U.S. has been effectively disrupted by attacking the leadership with stiff prison sentences, making the position not one to have. The leadership in Japan has not been attacked in the same manner.
This group is one of the richest underworld gangs in the world earning billions a year. The clan like all the other Yakuza groups have a serious effect on the economy of Japan, One tactic the Yaks have used has been to buy one share of stock in a company, than black mail the leadership with threats to disrupt shareholder meetings with dirt about either the leadership or thier dealings. This is a successful tactic in the conservative country. It was reported in Christopher Seymours Yakuza Diary, that the recession of 95 was called the Yakuza recession. The example cited was of a smaller bank that had folded after having $110 in bad loans, $70 million to organized crime. This group is also active in traditional organized crime, human trafficking, gambling,extortion, drug dealing, etc….
A documentary from Japan about the Yamaguchi-Gumi, it speaks to the structure of the clan.