Why are they called G6 countries?

The G6 countries, which include Canada, France, Germany, Italy, Japan, and the United Kingdom, were initially referred to as such when they were part of the Group of Six, a forum for discussing economic issues among major advanced economies. The term gained prominence in the 1970s and 1980s, particularly during global economic crises. The group later expanded to include the United States, becoming the G7, but the original designation of G6 remains in reference to that earlier coalition.