Answer
The WM formation, introduced by Herbert Chapman, revolutionized football tactics. It involved deploying a goalkeeper, two full-backs, three half-backs, and five forwards. This formation provided greater attacking flexibility, with wingers pushing forward to support the center-forward, while the half-backs dropped back to cover defensively. The WM formation became the dominant tactical system in the 1930s and 1940s, and its influence can still be seen in modern football.