Central control
Pawns and pieces that cover d4, d5, e4 and e5 restrict the opponent's pieces before any tactic exists.
White to play
d4
d4 hits e5 and frees the dark-squared bishop in the same move. Two jobs, one pawn.
What to look for
Count how many of your pieces and pawns hit d4, d5, e4 and e5, and how many of theirs do. The side with more usually has the freer game.
When it applies
In the first ten moves, and any time the position opens up. A pawn in the centre is worth more than the same pawn on the edge because it takes squares away from four enemy pieces at once.
How it goes wrong
Occupying the centre is not the same as controlling it. A pawn pushed to a square your opponent attacks three times is a target, not an asset.
Where it came up
Not cited in your current game.
Practise it
No positions yet. When you miss this idea in a game, the position it cost you shows up here — and in the practise set — with the answer hidden.