Opening preparation refers to the work done away from the board to study and memorize opening move sequences, with the goal of entering a game with a knowledge advantage or at least a familiar position.
In practice, this means learning the main lines of a chosen opening, understanding the typical ideas that arise from it — plans, active pieces, pawn structures — and preparing responses to the opponent’s most likely variations. For example, a player preparing the Sicilian Defense studies not just the moves 1.e4 c5, but also the different variations (Najdorf, Dragon, Scheveningen) and the positional plans associated with each resulting structure.
For players rated between 800 and 1400, it is far more effective to understand two or three openings deeply than to memorize a dozen of them superficially. The goal is not to recall long move lists, but to grasp the underlying principles: controlling the center, developing pieces quickly, and keeping the king safe. Solid opening preparation means spending less time on the clock in the early game and entering the middlegame with confidence.