Why did Guardiola paint lines on the training pitch?

Why would a world-famous coach paint lines on a training pitch? Because Pep Guardiola's positional play works like an invisible chessboard. In simple words, the pitch is divided into zones, with no more than two players on the same vertical line and no more than three on the same horizontal line.

Guardiola trained his players by painting lines on the training ground to show what the zones were. The training made it an instinct for players to find the zones where they could receive or play a pass. The guiding principle was efficient use of space: narrow it when defending, and expand it wider when attacking.

The lines are the visible part of an older idea. Johan Cruyff, a geometrical thinker, preferred a 4–3–3 or 3–4–3 because it is much easier to form passing triangles, which immediately give the receiver another option. He made rondos, the circle game where players try to keep the ball from one or two in the middle, the heart of Barcelona's training, though rondos were not his invention. And he pushed one central defender forward in possession to create a numerical advantage in midfield. As a youth, Guardiola was himself moved by Cruyff into the middle as pivot, a position few Spanish teams used.

What was the point? Guardiola explained it with a trick: overload one side of the pitch so the opponent tilts its defence to cope, drawing them in, then the other side is left weak. He even called recycling possession a defensive tactic in itself.