Ajax

The Dutch system from Ajax and the Netherlands national team in the 1970s, developed under Rinus Michels and Johan Cruyff. The core idea: any outfield player can swap into any other position. A defender becomes a midfielder, a midfielder becomes a winger, and so on. It demanded versatile players who could press together, spring the offside trap, and switch between attack and defence quickly. Still talked about as one of the sport's great tactical experiments, and it changed the way the world viewed football.