Hakkyokuseiken (Bājíshèngquán - "Eight Extremeties Holy Fist"; Japanese: 八極聖拳) is an unusual fighting style employed by fighters in the Fatal Fury, Art of Fighting and King of Fighters games produced by SNK.
Hakkyokuseiken is primarily based on Bajiquan (Hakkyokuken) and Tai chi chuan and has some mixes of other traditional kung fu styles incorporated in it. This style is mainly based on energy flow with a strong emphasis on Chi gung and each individual fighter uses it with his own fighting style. For example Tung Fu Rue uses it with various Chinese kung fu styles, Geese Howard incorporates it with his traditional Japanese martial arts, Terry Bogard uses it with his unique style of martial arts and street fighting, etc.
Hakkyokuseiken is an ancient kung fu style and it is recorded in an ancient scroll, which is passed down from master to chosen disciple and so on. Not all the techniques of this martial art are recorded in the scroll, the final techniques are taught directly by master to student. Hakkyokuseiken expects its students to be not only of powerful and skilled physical prowess but of strong mind, positive discipline and also good natured, not controlled by any negative emotions. The scrolls that have the art of Hakkyokuseiken recorded in them are apparently split in three different scrolls, the first part of the scroll contains the fighting techniques of Hakkyokuseiken, such as energy channeling and combat arts. Second scroll is to do with recuperation, which heals the fighter and also makes them physically stronger. Apparently this scroll is within the House Of Stroheim, in possession of Wolfgang Krauser and the final scroll, when combined with the other two scolls, contains the secrets to immortality which are in possession of the Jin brothers, Jin Chonrei and Jin Chonshu. Centuries ago these scrolls were stolen from the Jin family and they are now out to get them back by any means necessary, they hire psychopathic thug - Ryuji Yamazaki, who comes to Southtown with the Jin brothers to recover the scrolls.
Tung Fu Rue is the last known master of this system of fighting he uses the kung fu arts of Xingyiquan, Baguazhang, Bajiquan, Tai Chi Chuan, Iron Shirt , Iron Palm, shaolin crane and mantis style techniques into his art. Using the mastery of chi learnt from Hakkyokuseiken, Tung Fu Rue is able to use projectiles and energy blasts also use Qi to make himself and his spirit appear in a larger and more muscular form. Hakkyokuseiken teaches the practitioner to gather energy from the earth and all that is around them to create energy attacks and projectiles, even increase their own fighting prowess. This has allowed Geese Howard to take his fighting style into the next level, developing techniques such as Raging Storm, Double Reppuken and Hien Shippu Ken (Gale Fist). Terry Bogard was able to master the Power Geyser and also the Buster Wolf thanks to Hakkyokuseiken taught to him by master Tung Fu Rue.
- Tung Fu Rue - the most established and known master
- Jeff Bogard - Tung Fu Rue's chosen disciple
- Geese Howard - took it upon himself by dishonorable means
- Cheng Sinzan - a student of Tung Fu Rue's who was expelled because of his greed
- Wolfgang Krauser - possessed the second scroll of Hakkyokuseiken
- Terry Bogard - current known practitioner
- Rock Howard - Geese's son, Terry's protege and instinctual user of Hakkyokuseiken
- Jin Chonshu & Jin Chonrei - are descendants of the founder of Hakkyokuseiken
- Shun'ei - found him after his parents abandoned him for having an eerie powers related to the main antagonist of The King of Fighters series' 4th arc, currently raised him as one of Tung Fu Rue's current disciples, and master of an unique Hakkyoku fighting style, Hakkyokugen'eiken
- Meitenkun - one of Tung Fu Rue's current disciples, and master of an unique Hakkyoku fighting style, Hakkyokuminminken