The opening is the initial stage of a chess match (typically the first 10-15 moves) where players strive to develop their forces rapidly, contest control of the center, and secure their king's safety through castling. Opening puzzles focus heavily on exploiting early mistakes, identifying blunders in development, and navigating famous opening traps.
Many amateur games are decided in the opening because players fall into tactical traps or violate core principles (like moving the queen out too early or wasting tempos on unnecessary pawn moves). Solving opening puzzles trains your ability to spot development discrepancies, punish greedy setups, and build solid positions.