An imbalance is any meaningful, lasting difference between the two positions: bishop versus knight, structure versus activity, material versus initiative.
If both sides had identical pawns and pieces on mirrored squares, the game would be sterile. Real positions differ: one side owns the bishop pair, the other a better structure; one has material, the other the initiative. Jeremy Silman built a whole method on reading these imbalances and planning from them.
Imbalances tell you what to play for. The side with the bishop pair wants the position open; the side with the healthier pawns wants an endgame; the side with more space avoids trades. A plan that ignores your own assets fights the position instead of using it.
The Nimzo-Indian is a textbook factory of imbalances: Black concedes the bishop pair to double White's c-pawns. White then plays for open lines and the two bishops, Black for a blockade and pressure on the crippled pawns. Both plans are correct, because each follows its own imbalance.
The classic list: material, pawn structure, bishop versus knight, the bishop pair, space, development or initiative, and king safety. Most middlegame plans exploit one imbalance in your favor.
Name what you have that your opponent lacks, then steer the game where that asset matters: open the position for bishops, trade toward a superior endgame, or attack before your development lead fades.
BetterChess is a practice tool — we make no guarantee you'll reach 1800 or any rating. Definitions are standard chess terminology; every diagram position is checked legal with the same engine the board runs.