The National Soccer League is a name given to competitions in which New Zealand's top soccer clubs play each other, at least two times, on a home and away basis (and occasional in so called championship play-offs). At the completion of the competition, the best-performed team is declared as the New Zealand champion. Specifically, the name is usually used for the nationwide league competitions which ran intermittently from 1970 to 2004.
This definition, however, is open to debate. For example, in 2004, the New Zealand Football Championship was launched. Some do not consider this competition to be a true successor to the National Soccer League as it does not involve the traditional club teams but new teams especially created to compete in this competition. It also lacks a relegation and promotion system allowing clubs to "work their way up" and earn a place in this league (thus making the New Zealand championship a closed shop, eight team affair).
When the National Soccer League was launched in 1970, it became the first national league for any sport in New Zealand. It was also a league in the purest meaning of this word, as it involved clubs playing each other two times, on a home and away basis. Two points were awarded for a win, and one point was awarded for a draw. The club with the greatest number of points was declared the champion. The league was also open and clubs could be relegated from it and promoted to it. This is the most common method of deciding a national champion and prominent examples include the English Premier League, the Spanish La Liga and the Italian Serie A.
The league in 1970 involved eight teams. Three clubs came from the Northern League, three clubs came from the Central League while the four clubs from The Southern League (Christchurch City, Rangers, Shamrock and Technical) decided to back a new club called Christchurch United in the league. The last place went to the winner of a play-off of the fourth placed Northern League team, North Shore United, and the fourth placed Central League team, Hungaria. Hungaria succeeded by beating their opponents 1-0 in North Shore, and by drawing the return leg 1-1 at home.
The eight teams thus taking part in the inaugural National Soccer League were: Blockhouse Bay, Eastern Suburbs, Mt Wellington (promoted from the Northern League), Stop Out, Gisborne City, Hungaria, Western Suburbs (promoted from the Central League) and Christchurch United (representing the Southern League).