Sorry, I couldn't find yakuza-related books written in English. "Black Rain" is a good movie for Japanese yakuza. If you can see Japanese comic/Japanimation, "Emblem Take Two" is also useful.

Here is a short description for traditional Japanese yakuza

1. What the name "yakuza" mean?

   8-9-3. The word "ya" means "8," "ku" means "9," and "za" means "3." The name comes from "Oicho-Kabu," a Japanese gambling game like blackjack. Instead of 21, 19 is the strongest in Oicho-Kabu. Suppose that two cards are dealt to a gambler, "8" and "9", which make 17, a rather strong hand. But he decides to draw a more card. And comes "3", leaving a sum of 20. Now all is over. His hand is useless. This is the origin of the name "yakuza," useless hands in the society.

2. How yaks organize themselves?

   First, there are two types of yakuza, family yakuza and lone yakuza.

   The former is yakuza who belong to some families, like mafia.

   A family is structured as a real family in old traditional Japan. A family has a Father. It has also many children of the Father. There can be some brothers of the Father. The Father is the head of the family. All other members serve to the Father. In return, he protects every members in his family. Every members never fear to die for family and Father.

   If someone wants to become a member of a family, he must become a child of the Father. To do so, the newcomer and the Father drink a small amount of sake (Japanese alcohlic beverage) from a same cup. This ceremony is called "Sakazuki."

   Sometimes, a strong child has his own children, consisting his own new family. For example,

                       Big Father
                           |
               +-----------+------------+
               |           |            |
             child       child       child / Small Father
                                        |
                                   +----+----------+
                                   |               |
                                child            child
   

   A very powerful family can have a long chain of sub-families, child- families, grandchild-families, and so on. A typical family has 20-200 members, so the whole family group may count thousands of members.

   A lone yakuza has no family to belong. He has no companions to help him. Because yakuza is a organized business, going alone is not an easy way to live. No families permit a lone yakuza to operate in their territories. A competent yakuza can survive several years. Only a few genuine yakuza manages to build his own new family from zero.

3. What is "katagi"?

   "Katagi" is the opposite comcept of "yakuza." Usually all non-yakuza people are considered to be katagi. It is prohibited for yakuza to slay katagi people.

4. How yaks recognize each other?

   Anyone can easily tell low-ranked yakuza from the katagi. They are so conspicuous. High-ranked yakuza are difficult to tell. Their behavior and fashion are moderate. But their rank is so high that their faces are known to all yakuza.

   To recognize yakuza's families, there are "daimon," family emblems. Each family has its own daimon, and family members have small badges of their family daimon. High-ranked members are permitted to have golden badge. Daimon is the primary identifier of yakuza families.

5. What yaks do?

   Protection racket is the most important money source of yakuza. Other sources are varies from family to family. It depends on the origin of the family.

   There are four major origins of yakuza. Yakuza operation is basically based on the origin of their family.

   • Bakuto
   • Tekiya
   • Uyoku
   • Gurentai
   
   "Bakuto" means "gambler." Throughout the Japanese history, gambling has been illegan, thus in yakuza's territory. Owners of gambling houses, bankers and bodyguards formed Bakuto yakuza. The primal activities of Bakuto yakuza are gambling houses (of course), bucket shops, loan shark, collecting debt etc.

   "Tekiya" means small merchants who opened street stalls at festivals. When a festival was held in a city, many Tekiya merchants gathered there. Tekiya yakuza was the boss of such Tekiya merchants. Each merchant paid small fee to open his stall. In return, Tekiya yakuza protected them during the festival. As Japanese society was industrialized, Tekiya yakuza expanded their protection racket. Now they have their strong territories in cities and demand protection fee to all shopkeepers in their territories.

   "Uyoku" means political right. They are nationalists, traditionalists, monarchists (emperor), and anti-communists. They believes the Pacific War was the holy war to protect Asian nations from Western imperialism. They also hate megacorps. Big media corporations are the primal target of Uyoku yakuza attack. Their money sources are in mystery, but it is rumored that they have strong connections with politicians.

   "Gurentai" means "city thugs." They are grouped violent thugs. Bakuto/Tekiya families often have their long traditions. Gurentai don't. They have no policy, so do anything for money. Corporations use Gurentai yakuza for various purposes. They are so useful.

   Prostitution, drug dealing, blackmailing and badger game are also yakuza's common activities.

6. What yaks do not?

   Theft and robbery are considered "shameful." They intimidate and blackmail instead.

   Murdering katagi people was strictly prohibited by code of honor. The code, however, is often ignored today. Murder for insurance money is not rare recently.

7. What yaks hate?

   To be insulted. Disgracing himself.

   A yakuza cares his reputation very much, because his income relies on how he is feared by others. When he is made light of, he ends.

8. I'm now threaten by yakuza. What can I do to escape?

   Hire another yakuza. Competent one is desirable. He will negotiate and solve your problem in peace.

   Of course it is not free. The more competent yakuza you hire, the higher commission rate he demands. But whole expenses will be lower at last.

9. Tell me yakuza titles and slangs

   Chaka/Hajiki

   guns, especially pistols

   Dosu

   katana, sword

   Fuda

   search/arrest warrant

   Kagechofu

   money paid to a imprisoned yakuza from his family

   Kanbu

   executive members in a family permitted to have golden badge of daimon

   Kiritori

   collecting debt

   Kumicho

   the head of a family, Father

   Kyoudai

   brother

   Musho

   prison

   Nomiya

   bucket shop

   Ojiki

   uncle (father's brother)

   Otsutome

   the term of imprisonment

   Oyaji

   Father

   Senso

   war between yakuza families

   Satsu/Pori

   police

   Shabu

   drug

   Shatei

   small brother

   Shatei-gashira

   the chief of Kumicho's brothers in a family ranked higher than Waka-gashira, but with less power

   Shima

   territory, protection racket

   Teuchi

   armistice

   Tsutsumotase

   badger game

   Wakashu

   child

   Waka-gashira

   the chief of children in a family usually No.2 in the family

   Yusuri

   blackmailing