Elaborate tattoos are probably the most well-known. Here is a brief history behind Yakuza tattoos (video, two minutes). https://www.youtube.com/watch? read more
In some cases a person expelled from a yakuza gang might be required to perform the yubitsume ritual. The finger of the yakuza directly responsible for an offense is called an iki yubi, "living finger", while the finger of the yakuza that is directly in charge of him is called a shinu yubi, "dead finger". read more
Yakuza groups are organised using a hierarchical structure that works much like a family. Each recruit is referred to as a kobun (child), and has a father, known as oyabun. This parent-child relationship operates throughout every level of the yakuza, from top-level conglomerate bosses (known as kumicho), all the way down to new recruits. read more
Yakuza have a complex leadership structure, and there are many layers one must progress through to reach the top. The initiation ritual for a new recruit is a ceremony based around sake, known as sakazukigoto. read more