RULESETS

Japanese kickboxing is combat sport created by the Japanese boxing promoter Osamu Noguchi and Tatsuo Yamada (Karate practitioner). It was the first combat sport that adopted the name of "Kickboxing" in 1966, later termed "Japanese kickboxing" as a retronym. Japanese kickboxing has developed into K-1 in 1993.

These rules are almost same as Muay Thai rules:

    Similarities
        Time: three minutes × five rounds
        Allowed to kick the lower half of the body except crotch
        Allowed to do neck-wrestling (folding opponent's head with arms and elbows to attack the opponent's body or head with knee-strikes, but only depending on the rules of clinch and knees)
        Allows knee strikes
        Head butts and throws were banned in 1966 for boxers' safety.

    Differences
        No ram muay before match
        No Thai music during the match
        Interval takes one minute only as same as boxing
        Point system:

            In Muay Thai, kicking to mid-body and head are scored highly generating a large number of points on judges' scorecards. Moreover, kicking is still judged highly even if the kick was blocked. In contrast, punching is worth fewer points. In kickboxing punches and kicks are held in closer esteem.

American kickboxing

In the full-contact sport the male boxers are bare-chested wearing shorts and protective gear including: mouth-guard, hand-wraps, 10 oz (280 g). boxing gloves, groin-guard,butt-guard and optional shin-pads, kick-boots, protective helmet (usually for those under 16). The female boxers will wear a sports bra and chest protection in addition to the male clothing/protective gear. In international kickboxing, where kicks to the thigh are allowed using special low-kick rules, use of Thai shorts instead of long trousers is possible. In addition, amateur rules often allow less experienced competitors to use light or semi-contact rules, where the intention is to score points by executing successful strikes past the opponent's guard, and use of force is regulated. The equipment for semi-contact is similar to full-contact matches, usually with addition of headgear. Competitors usually dress in a t-shirt for semi-contact matches, to separate them from the bare-chested full-contact participants.[14]

These are the rules used in American full contact karate.

    Opponents are allowed to hit each other with fists and feet, striking above the hip
    Using elbows is forbidden and the use of the shins is seldom allowed.
    Bouts are usually 3 to 12 rounds (lasting 2–3 minutes each) for amateur and professional contests with a 1-minute rest in between rounds.

This is in direct contrast to Muay Thai, where the use of elbows and knees are allowed. In fact, some Muay Thai practitioners consider American kickboxing a "watered down" version of Muay Thai. Fighters and promoters can agree to various rules including kicks only above the waist, kicks anywhere, no knee strikes, knees only to the body, and so on. American kickboxing is essentially much a mixture of Western boxing and traditional karate.

The round durations and the number of rounds can vary depending on the stipulations agreed to beforehand by each fighter or manager. A winner is declared during the bout if there is a submission (fighter quits or fighter's corner throws in the towel), knockout (KO), or referee stoppage (technical knock out, or TKO). If all of the rounds expire with no knockout then the fight is scored by a team of 3 judges. The judges determine a winner based on their scoring of each round. A split decision indicates a disagreement between the judges, while a unanimous decision indicates that all judges saw the fight the same way and all have declared the same winner.
International ruleset
Further information: International Kickboxing Federation

The "international kickboxing" ruleset by the International Kickboxing Federation contrasts with the American kickboxing rules in that it allows also low kicks.

These are the rules for international rules kickboxing.

    Opponents are allowed to strike their opponent with punches and kicks, including kicks below the waist, except for the groin.
    Knees, elbows or clinching are not allowed.
    Bouts are 3 to 5 rounds for Amateurs and 3 to 12 rounds for professionals, all rounds lasting 2 minutes each. Each round has a 1-minute rest in between rounds.

Other kickboxing styles

Semi contact:

    See "IKF Point Kickboxing"

Semi-contact is a fighting discipline where two fighters fight with the primary goal of scoring greater points using controlled legal techniques with speed and focus. The main characteristics of semi-contact are delivery, technique and speed. The competition in semi-contact should be executed in its true sense with light and well-controlled contact. It is a technical discipline with equal emphasis put on hand and foot techniques from an athletic viewpoint. Techniques (punches and kicks) are strictly controlled. At each valid point (a point that is awarded, with a legal part of hand or foot to legal targets and with legal technique), the central referee halts the fight and at the same time as the two judges, shows with his/her fingers the number of points in the direction of the fighter who is being awarded points. Fighters will enter the tatami and touch gloves. They will then step back and assume a fighting stance and wait for the command FIGHT from the referee. The time will only be stopped on the command of the referee, by calling TIME toward the area control table. Time is not stopped to award points or penalties unless the referee feels it is necessary. A fighter may have one coach and one second in his corner during the match.

Light contact (or medium-contact)
Competition in Light Contact kickboxing should be executed as its name implies, with well-controlled techniques. In light contact competitors fight continuously until the central referee commands STOP or BREAK. They use techniques from full contact, but these techniques must be well controlled when they land on legal targets. Equal emphasis must be placed on both punching and kicking techniques. Light contact has been created as an intermediate stage between semi and full contact kickboxing. It is carried out with running time. The central referee doesn't judge the fighters, but only makes sure they respect the rules. The fight could be held in a tatami or in a ring.