Unlike other combat sports, kickboxing is hardly an unified discipline: it developed under several forms in very disparage countries and time periods, often with little to no direct contact to each other, which resulted in a myriad of circuits that only gain the appellative of kickboxing by sharing a vaguely similar punch-and-kick ruleset. To blur the lines even more, many traditional martial arts contain elements that would fit this definition as well, like Karate, Muay Thai, Taekwondo and some more, with several of them having contributed actively to their nearest kickboxing style. In synthesis, it is more correct to talk about kickboxing forms, just as "wrestling" can convey a variety of fighting systems instead of an overarching sport.
The term "kickboxing" was a Gratuitous English term created in The '60s by Osamu Noguchi, a Japanese promoter that codified most of the aspects we associate with modern kickboxing. The discipline he would go to promote was shaped by Tatsuo Yamada, a karateka who became fascinated with the full contact nature and liberal rules of muay thai. With their influence and that of several publicized challenge matches between karatekas and nak muay, Japan saw the creation of a Kickboxing Association and the rise of a new, exciting professional sport, whose popularity exploded right then and didnt burn off completely until The '80s. Even then, the seed remained deeply planted, and when Akira Maeda and his collaborators broke off from Professional Wrestling to entertain the idea of real fighting, the return of kickboxing was one of its consequences. With the help of Maeda, a modernized organization named K-1 blossomed, attracting fighters from around the world and exploding in its own boom of fighting culture, dream matches and bone-breaking kicks.
At the same time, United States witnessed a similar evolution. Although some minor martial artists had attempted to create something similar, it was again a disenchanted karateka from The '70s, Joe Louis, who had the idea (inspired by his training under Bruce Lee) to combine elements of karate and boxing. His creation was initially conceived as a form of full-contact karate, with the term kickboxing being an exotic term that ended up sticking; it was not until the founding of the Professional Karate Association (PKA) and the World Kickboxing Association (WKA) that their road became bifurcated and took separate directions. Other acronyms like IKF and ISKA appeared around this time, shaping it as a relatively popular competition circuit. It is interesting to note that, despite its revolutionary beginning, American kickboxing would differentiate itself from foreign forms by its conservative ruleset, which forbad kicks around the waist and barely allowed striking tools other than fists and feet. This would be a further point of evolution when one of its main stars, Benny "The Jet" Urquídez, made contact with muay thai fighters.
Meanwhile, the rest of the world was taking its own notes. Dutch martial artists influenced by Jon Bluming discovered in mid-80s the remnants of the Japanese circuit and its Thai neghbours, and after deciding it was the coolest thing around, they put their efforts in learn whatever they could and recreate with their own arts what they could not. A long tradition of kickboxers started there, marked by but not limited to a legendary rivalry between Thom Harinck's Chakuriki team and Jan Plas's Mejiro Gym. With the rise of K-1 and the the Japanese branch of Mixed Martial Arts, those Dutch badasses decided to give back more than they had taken and joined them in the journey.
Nowadays, the main styles or forms of kickboxing are the following ones. Note again that, as mentioned before, traditional martial arts like muay thai and karate can be considered kickboxing modalities as well.
- Full contact or American kickboxing: born in the United States, this style is, as mentioned before, conservative in its rules and based on karate competitions. Its fighters wear long trousers with shin pads and boxing gloves, as well as protective helmets if they are amateur or under 16. On the ring, they can use only punches and kicks (usually with the foot, although the shin is sometimes legal too), and kicking about the waist is forbidden altogether. Clinch-fighting is similarly forbidden, but sweeps can be allowed depending on the ruleset. There is also a variation named semi-contact, with a slightly more closed ruleset, where gaining points is the main way to win.
- High kick only: a now-extinct form of American kickboxing, and was once the predominate style until the rise of the WKA. This form had the same target area as normal boxing, that is, no kicks at or below the waist. The PKA were the main proponents of this style, which some cynically argued was to protect their middleweight champion, Bill "Superfoot" Wallace, and it more or less died with them.
- International or freestyle kickboxing: popular in European countries outside Netherlands, it is essentially a customized version of American kickboxing. Its ruleset is similar, except that it allows kicking to the legs and disallows sweeps.
- Oriental, K-1 or Japanese kickboxing: created by the Japanese and adored by the Dutch, it is the originator of the kickboxing name. Fighters here wear mainly boxing shorts, although trousers and even full karategi used to be legal, often causing a surprising visual diversity. This style is substantially open: fighters can hit with punches, kicks, knees to any part except by the groin, and a limited amount of clinching is allowed (throws and sweeps used to be legal at their beginnings). Back in the 80s, its main promotion K-1 was essentially the Mecca of kickboxing, so this modality is probably what most non-American fans see when they think about the sport.
- Shootboxing: an unique Japanese variation created by former kickboxer Caesar Takeshi, who had connections to the Japanese wrestling environment that gave birth to Mixed Martial Arts. The most open of all the kickboxing forms, shootboxing allows punches, kicks, knees, elbows, clinching, throws, sweeps and even submission holds (as long as they are finished standing), and their fighters are clad in pro wrestling-esque long tights. This used to be a very niche sport compared to the other forms, but it has become bigger through the years, and nowadays it has a significant pool of talent.
- Sanshou or Sanda: A Chinese variation similar to Shootboxing, just without the standing submissions. Originally developed as a military fighting system based on the study of various styles of kung fu, for some reason it was decided that the sport version was to be kickboxing-like, with the addition of throws, takedowns and sweeps. Uniquely, matches can take place in either a boxing ring or an elevated platform called a lei tai, which is basically a ring without ropes and is a throwback to the old days of Chinese kung fu duels. Matches on the lei tai contain different rules, for it allows (in fact encourages) throwing opponents off the platform to score points and/or defeat the opponent should they be thrown off enough times. Like Muay Thai in Thailand, it is the most popular combat sport in its country of origin and it has steadily been growing its pool of talent on the international scale since the 90s.
- Draka: a slightly modified version of sanda developed by a few Russian practitioners. It gained a bit of attention due to a few PP Vs in the US, though kind of dropped out off the map after those events for a while. However, it now seems to have further evolved into a more MMA-style sport resembling pre-1994 Shooto, thanks to its limited ground time, though without knockdown counts in pro rules (amateur rules apparently each fighter is allowed two standing eight counts before the next knockdown means defeat) and with the allowance of ground-and-pound.
- Savate or Boxe Française: A French variation with an interesting history and distinct appearance, with other names like Jeu Marseillais ("Game from Marseille") and chausson ("slipper") in its early days. Originally developed by French sailors for street fighting, mainly based on kicks and palm strikes as the French government had considered that the closed fist was an illegal deadly weapon at the beginning of the 19th Century. It later added English boxing to its curriculum to eventually became the modern sport version seen today. Official competitions use the intégrale (looks like a wrestling singlet with long pants) or a customized vest and trousers combination as the uniform, and is the only kickboxing-like sport where shoes are not only legal, but mandatory. Competitions also make practitioners use a rather limited arsenal, as there are only four kinds of kicks allowed (all foot kicks) along with four kinds of punches allowed, though the best practitioners know how to get creative with them.