The later you blunder, the more it costs you. A player's worst move is worth about four and a half pawns in the opening stretch of a game. By the closing stretch of the same game it is worth about eight pawns, a rook and a bishop instead.

The later you blunder, the more it costs you.

A player's worst move is worth about four and a half pawns in the opening stretch of a game. By the closing stretch of the same game it is worth about eight pawns, a rook and a bishop instead.

Walk a game from start to finish in five stages and the damage climbs at every one: about four and a half pawns in the opening stretch, then more, then more again, until the last fifth costs about eight pawns, a rook and a bishop. It is not simply that long games contain more mistakes. The same mistake is worth more when it arrives late, because by then there is less position left to recover in and usually less clock to find the recovery with.

Across 358,443 analysed games from 241 players.

The Position

Black to move and win.

Black to move · rated 1704.

The answer runs in tomorrow's issue.

Eloist puzzle deck

The Opening Files · No. 7

Getting winning is not the same as staying winning.

For the typical player in the corpus, 25.0% of the games in which they reached an advantage of at least three pawns finished with the evaluation back at level or worse, measured over 242 players and 290,136 such games.

The middle half of players sit between 20.4% and 30.9%, so this is a habit nearly everyone has rather than a few people dragging an average. Pooling every game instead gives 25.5%, near enough the median that no one prolific account is carrying it. Only positions from move five onward count as the peak, so opening noise cannot qualify as winning, and the endpoint is the final evaluation rather than the result, which also turns on the clock.

Across 290,136 analysed games from 242 players.

From the Files

In the Latvian Gambit Accepted, the Lichess archive holds 1.2M club games (1600–2000) that reach this position. The top reply e4 is chosen 57% of the time and scores 53% for Black.

The Opening Files runs again tomorrow.