K-1 is a world-wide kickboxing promotion founded in Tokyo, Japan by Kazuyoshi Ishii, a former Kyokushin karate practitioner. Its rules are similar to those of kickboxing but they have been simplified to promote exciting matches that may end in a knockout win. The main difference between K-1 rules and kickboxing is the use of knees, allowed in K-1 but not in International kickboxing.

There are K-1 Regional Elimination Tournaments which qualify fighters for the K-1 World Grand Prix, along with licensed K-1 Fighting Network events designed to develop new talent internationally and there is also a 70 kg (154 lb) Middleweight division called K-1 MAX ("Middleweight Artistic Xtreme"). In 2007, K-1 introduced two new Title belts separate from K-1 World GP Champions, Super Heavyweight World Title for fighters over 100 kg/220 lbs and Heavyweight World Title for fighters under 100 kg/156–220 lbs.

The letter K in K-1 is officially designated by the organisation as a representation of words karate, kickboxing and kung fu. Nevertheless, some reports suggest that it represents the initial K found in competing disciplines such as karate, kickboxing, kung fu, kempo, kakutogi (the generic Japanese term for "combat sports"), and [tae] kwon do. Yet another theory claims that the K simply comes from kakutogi and the "1" component pertains to the single weight division (in earlier competition) and the champion's unique position.

Buakaw Banchamek (Thai: บัวขาว บัญชาเมฆ, born May 8, 1982) is a retired Thai welterweight Muay Thai kickboxer, who formerly fought out of Por. Pramuk Gym, in Bangkok, Thailand under the ring name Buakaw Por. Pramuk (Thai: บัวขาว ป.ประมุข). He is a former Omnoi Stadium champion and two time, 2004, 2006 K-1 World MAX champion.

Born as Sombat Banchamek (Thai: สมบัติ บัญชาเมฆ) in Surin,Thailand, Buakaw started his fighting career at the age of eight in his home province of Surin in the northeastern Thailand. He moved to Chachoengsao when he was 15, and since then he has been with the Por. Pramuk Gym. His first fight name was Damtamin Kiat-anan.

Buakaw has collected several belts to his name since fighting in Bangkok. The Omnoi Stadium featherweight title was his first belt, after that he would go on to take the featherweight champion of Thailand title. Buakaw then proceeded to win another Omnoi Stadium title belt, this time at in lightweight division. In December 2002, Buakaw won the Toyota Marathon 140 lb. tournament at Lumpinee Boxing Stadium, beating the highly regarded Kobayashi of Japan in the final.

Badr Hari born December 8, 1984 in Amsterdam, Netherlands is a Moroccan-Dutch super heavyweight kickboxer from the Netherlands, fighting out of Mike's Gym in Amsterdam. He is a former K-1 Heavyweight champion (2007—2008) and K-1 World Grand Prix 2009 finalist. As of May 2011, Hari is ranked the #2 heavyweight in the world by LiverKick.com. Hari has been a prominent figure in the world of kickboxing and considered one of the best kickboxers in the world, however he has been involved in a number of controversies relating to his "unsportsmanlike conducts" in the sport and alleged crimes of violence outside of the ring.

He was disqualified in the final match of the K-1 World GP 2008 Finals due to "unsportsmanlike conduct" against Remy Bonjasky. In May 2009 he knocked out Semmy Schilt in the first round and became the first ever It's Showtime World Heavyweight champion. However he lost this title when he was again disqualified after another unsportsmanlike conduct against Hesdy Gerges at the It's Showtime 2010 Amsterdam. Aside from the sport, he has been arrested multiple times since 2006 on various assault charges against others.

Zabit "Maugli" Samedov (Azeri: Zabit Səmədov, Russian: Забит Самедов, born June 21, 1984) is an Azerbaijani kickboxer fighting out of Chinuk Gym in Minsk, Belarus.

Zabit Samedov was born in Georgia into an Azeri family and moved to Minsk when he was 10 years old. He started practicing martial arts at the age of 9. At very first he studied karate for 6 months under Aziz Dursunov, then switched to Muay Thai. In 1998, he joined Chinuk Gym, a well known gym based in Minsk. He trained with Alexey Ignashov and Sergei Gur under the management of his trainer Dmitriy Pyasetsky.

He was recruited by top martial arts organization K-1, after achieving several titles in various events between 2004 and 2006. He began to fight with consistency by attaining the title of K-1 Fighting Network in Riga in 2006 in Latvia.

On 26 April 2008, Samedov competed in K-1 World Grand Prix 2008 in Amsterdam, dispatched Doug Viney and Brian Douwes respectively. However, he was beaten by Errol Zimmerman in the final on points.

Mark Hunt (born 23 March 1974) Japanese: [Mākuhanto]; is a New Zealand kickboxer and mixed martial artist of Samoan descent, currently living in Sydney, Australia. Hunt competes in the Ultimate Fighting Championship and is known for his raw strength, iron chin and knockout power. He is the winner of the 2001 K-1 World Grand Prix. Hunt was the first to beat Wanderlei Silva after his 4 year undefeated winning streak in Pride Fighting Championship. He holds notable wins over the likes of Mirko Cro Cop, Ben Rothwell and Cheick Kongo.

Hunt was born in St Helens Auckland, into a small, Samoan family. He and his family then relocated to a tough suburb within South Auckland, New Zealand. He was a troubled kid and had no intentions to be a professional fighter, until one late night altercation outside a nightclub in Auckland changed the course of his life. The brawl did not last long. Sam Marsters, one of the bouncers at the door was impressed by the young man's knockout power and invited him to his Gym to take up formal training. Later that year Hunt moved to Sydney, Australia, to train with Alex Tui. A few years later he settled in Liverpool Kickboxing Gym under Maori instructor Hape Ngaranoa.