The Korea National League is a semi-professional football league, the second tier of South Korean football league system, consisting of fourteen member clubs. The season is composed of two sections with the fourteen member clubs playing each other once in each section. The two section winners and the two runners-up from both stages progress to the post-season season playoffs to decide the league champion. In the event of the same team winning both sections, that team is pronounced champion without the need for the playoffs.
Korea National League has been named after its sponsor, giving it the following names:
- Intermax K2 League (2003), sponsored by Intermax AD
- Hyundai Motors K2 League (2004), sponsored by Hyundai Motor Company
- Kookmin Bank K2 League (2005), sponsored by Kookmin Bank
- STC Korea National League (2006), sponsored by STC Life
- Kookmin Bank Korea National League (2007-2008), sponsored by Kookmin Bank
- Kyobo Life Korea National League (2009), sponsored by Kyobo Life Insurance
- Daehan Life Korea National League (2010), sponsored by Hanwha Daehan Life
The league was officially founded in 2003 as the K2 League, to raise the level of competition in Korea. Prior to that, various cup competitions were run by the governing body of semi-professional football. Competitions under the present body can be traced back to 1990, with the participants being mostly works sides of the major industries in Korea (banks, construction companies and the like). It was rebranded Korea National League at the beginning of 2006.
It had operated with a two stage season since its inception, with the two stage winners meeting in a two-legged championship playoff final at the end of the season before changing to a four team playoff in 2008. Kookmin Bank won the 2003 championship, and successfully defended their title in 2004. Incheon Korail claimed the title in 2005 before Kookmin Bank won it for a third time in 2006. Ulsan Mipo Dockyard won the championship in 2007.
On December 18, 2009, The league approved to join 2 clubs, Mokpo City FC & Yongin City FC, from the 2010 season.
Ever since the creation of the league, hopes had been high that a system of promotion and relegation would be implemented between the league and the K-League, the professional football league in Korea. In 2006, it was agreed that, subject to meeting certain financial requirements, the National League champions would be eligible for promotion. Goyang Kookmin Bank, who triumphed over Gimpo Hallelujah to win the 2006 title, were the first side eligible for promotion, however they controversially rejected the chance to return to the professional ranks.
The team received several threats from the National League ranging from being thrown out of the competition, to fines, to point deductions for the upcoming 2007 season. In the end the side received a points deduction penalty, to be split into ten point deductions in the first and second stages of the 2007 season.
Following the case involving Goyang, teams in the National League signed agreements indicating whether or not they would seek promotion to the K-League if they win the National League in 2007. Ulsan Mipo Dockyard, who won the championship in 2007, also rejected the chance to move up to the K-League despite previously indicating they would seek promotion.
In light of the issues surrounding the conditional promotion place in 2006 and 2007, the National League decided to end the system prior to the 2008 season.
On November 2, new commissioner, Kwon Oh-Gab, announced to push implementing a promotion system with K-league within 3 years.