Already in 1978, there was a merger of the topflight NFL and NPSL, to form the first non-racial division for the First Level of South African football. The new common topflight league, was named NPSL Castle League in 1978-84, and renamed to NSL Castle League in 1985-95. In the early years from 1978-1986, relegation/promotion to and from the topflight non-racial football league, according to official recordsactually did happen, but apparently it still happened from a Second Level league structure, divided into whites/blacks/coloureds. The NSL Second Division began in 1985 as a feeder to the then top tierNational Soccer League. In March 1987, the naming rights of the division were sold to South African Breweries who also sponsored the NSL's top tier league with their Castle Lager brand, the competition was titled the OK League after the brewery's bazaar chain "OK Bazaars". It is claimed by the Premier Soccer League that the division was the first non-racial Second Level of South African football. Teams were promoted to the NSL Castle League from the Second Division, and those relegated from the Castle League would compete in the Second Division the following season. The competition was originally an individual league table but in 1990, it was felt that the league was becoming too expensive to run and it was decided that the competition should be split into regions. As a result, the number of teams increased from 17 in a single league to 40 divided into two divisions. These divisions were named "O" and "K" as part of the title sponsor's marketing campaign. In 1995 the league was diluted further and developed into four geographical streams, each comprising 19 clubs. In the space of six years the number of participating teams had risen from 17 to 76. When the National Soccer League competition was rebranded in 1996, the organizers also replaced the NSL Second Division. It became the new National First Division. Apart from a new name and a better sponsor deal, the most significant change -both at the First and Second Level- was to change the fixture schedule from yearly seasons, into the more commonly used International standard of September–May seasons.
