According to the writer Atsushi Mizoguchi,
the name derives from the union of three
words: ya ("eight"), ku ("nine") and sa ("three").
THESE THREE NUMBERS REPRESENT the losing score in
a very popular card game in mafia-controlled gambling
dens called Hanafuda. in the news and in the writings,
however, you will often hear the word bōryokudan (暴力 団
which means “violent group”.
The Yakuza system is that of the patriarchal family, where roles are not questioned and obedience to the rules is blind. However, unlike other criminal organizations, the connection is not of blood. its members do not hide. In Japan it is normal for adepts to present their business card, have an official logo and do not hide their boss or their headquarters.
Tattoos known as irezumi (from ireru, "insert", and sumi, "ink") are often made using hand-made, non-electric tools with bamboo or sharp steel needles. The procedure is very expensive, painful and can take years to complete. The tattooed skins of dead yakuza members would even have a black market as a display commodity in some art galleries.
The yubitsume (指 詰 め "shortening of fingers") is a ritual to atone for the guilt of serious misconduct towards the organization. it is a way to be punished or to show sincere apologies and consists in the amputation of the phalanges of one's little finger.