Post-mortem analysis is the critical review of a chess game carried out after it has ended, with the goal of identifying mistakes, missed opportunities, and key turning points.
The process involves replaying the moves — either on a board or with software — and comparing the decisions made to stronger alternatives. The focus is on finding the critical moments where the game could have taken a different course. For instance, if a player missed a winning fork on move 20, post-mortem analysis helps pinpoint that tactical pattern and understand why it went unnoticed during the game.
In practice, players rated 800–1400 are strongly encouraged to analyse their games using an engine such as Stockfish, available on most online platforms — but not to rely on it blindly. The recommended approach is to first identify the key moments independently, then check those conclusions against the engine. This method builds self-evaluation skills, which are one of the cornerstones of chess improvement.