I noticed a recent trend in the English speaking Street Fighter fan community. Particularly fansites, wikis, forum posters, and even bloggers on this very site, have use the term "ansatsuken" as it was the name of Ryu and Ken's fighting style. It even made it in a fanmade trailer for the American developed Street Fighter II HD Remix. This is incorrect and I will explain why.

First, we must understand the meaning of the term ansatsuken (暗殺拳). Its a rather recent Japanese neologism that literally means "assassination fist" or "assassination art". The term ansatsuken has actually been used in martial arts related fiction. One of the earliest use of the term was in the 1980's manga and anime classic Hokuto no Ken (known in the west Fist of the North Star). The martial art style used by the main character, Hokuto Shinken, is described in the series as the "assassination art with only one successor" (一子相伝の暗殺拳, isshisouden no ansatsuken). The term ansatsuken has also been used in various other Japanese fiction. Avenger, the first installment of the Way of the Tiger game books was officially translated under the title Tiger Ansatsuken.

"Naruhodo, kisama ga ano densetsu no ansatsuken Hokuto Shinken o tsukau otoko datta (I see, so you're the man who uses Hokuto Shinken, the legendary art of assassination)" says the Colonel to Kenshiro. The Colonel uses the synonymous term satsujinken (殺人拳, murderer's fist) to describe his own style.

The term ansatsuken was first used to describe Ryu and Ken's style with Gouki's (Akuma) introduction to the series in Super Street Fighter II X (or Super Turbo) . To explain why Gouki used more powerful versions of Ryu and Ken's special techniques, a back story was developed which characterized him as the younger brother of Ryu and Ken's sifu Gouken. As you may or may not know already, Gouki and Gouken were students of Goutetsu, a martial arts master who trained the two in an ancient assassination art (or ansatsuken). Gouken, seeking to turn the fighting style from a murderous art to a sublimed martial art by refining the art's three secret techniques and removing the murderous energy (殺意の波動, satsui no hadou) they originally possessed.

The term is used in relation to Ryu and Ken's fighting style, not as the name of a specific fighting style or school, but simply as a classification and ansatsuken and sastsujinken have both been used to describe his fighting style. Using the term "ansatsuken warriors" to describe the Ryu-type characters in the series, or listing "ansatsuken" as Ryu's fighting style is misleading for several reasons.

Only Gouki actually uses the original murderous style, while Gouken, Ryu, and Ken, all use a sublimated form of the same style which Gouken developed. Ryu and Ken's fighting style is not actually a murderous style, but simply a martial art which has its roots in an assasination art, which is a big difference. Unless you count Evil Ryu of course, which is the version of "Ryu created from Satsui no Hadou who's gone to the dark side of Gouken's arts once used for assassination" as Card Fighters DS so elonquently put it. Even Gouken's official description for Street Fighter IV says as much.

Ryu and Ken's master and Gouki's own brother. Refining the techniques which were once used for assassination (ansatsuken), he developed them into a first-class martial art, which he then taught to Ryu and Ken. Defeated by Gouki, he was believed to be dead, but has appeared once again.

As you can see, Gouki's style was an "ansatsuken", but isn't anymore. The fact that characters like Sakura, Dan, and Sean, are all classified as "ansatsuken practioners" shows an ignorance of the term.

The second reason why its misleading is because there's another martial art style in the series which has been classified as an ansatsuken. I'm talking about Gen's of course.

The two fighting styles used by Gen in Street Fighter ZERO 2 (Alpha 2) are referred as ansatsuken sou ryuu and gi ryuu (Mourning style and Hateful style respectively).

Even before his return in ZERO 2, Gen's martial art style was describe as an ansatsuken in his first appearance in the original Street Fighter, years before Gouki's first appearance in the series and the origin of Ryu's martial was established. So the term "ansatsuken warrior" is just as fitting to Gen as it is for Gouki. Its no wonder why these two were made into rivals in the Alpha series.

So if "ansatsuken" isn't the official name of this Ryu's style, then which is it? It doesn't have one. Just like Yoda from Star Wars is a member of a nameless specie, the name of the fighting style used by Ryu and all related characters has never been given an official name.

What about Shotokan Karate? That was merely a localization liberty in the instruction manual for the SNES version of Street Fighter II, just like how Dhalsim's fighting style was listed as Khabbadi in the same manual (Khabbadi is actually a sort of Indian version of tag). Oddly enough, the term shotoclone is still used despite that.

What about Goutetsu-ryu ansatsuken? A completely fanmade term and misleading since it suggest that Goutetsu created the fighting style. However Ryu's win quote against Guile in the Japanese version of Capcom vs. SNK 2, as well Zero's pre battle dialogue in SvC Chaos, both suggest that Ryu/Gouki's fighting style was created during the feudal age in Japan, long before Goutetsu was even born (Zero's dialogue in Chaos was mistranslated though in the English version, and Ciel seems to suggest that Akuma himself is from the middle ages).

The fighting style has no name and it doesn't need one. The fact that it has no name actually adds some mystique to its origin.