Throughout its existence the group retained a definition of being standard, series production touring cars, and of having a character of being unmodified or not specifically prepared for racing.
The class was introduced in the then new Appendix J of the International Sporting Code in 1954 and was replaced by Group N in 1982.
[1][2] From its inception in 1954 until 1965, Group 1, officially documented at first as the first group, was included in Category I (or A), Touring Cars, with a production requirement of between 600 and 1000 cars in a 12 month period.
[2] The two categories had up to six groups in this time era, but not consistently or retaining the same definitions.
Group 1 essentially remained the same in character but with a heightened production requirement of 5000 cars.