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How to win a won game: what 150,000 games say about converting

"Winning a won game is the hardest thing in chess" is an old saying. Our counts of 150,000 online games show it's true at every rating, and they show where the 1600s and 2000s pull away.

How we counted

A level position is within two pawns either way, by the engine's count; clearly ahead is two to six pawns up; three pawns ahead is used for converting wins. A slip costs at least 10 points of winning chances, out of 100; a blunder costs at least 30. Numbers are from rapid games unless labeled. Ratings are Lichess ratings.

Everyone gets careless when ahead

Among 100 players, 20 at each rating level, the blunder rate once clearly ahead was about two and a half times the rate in level positions, at every rating:

Blunders per 100 moves (blitz, typical player)Under 800800–11991200–15991600–19992000+
Level position8.04.43.02.11.3
Clearly ahead18.911.18.25.63.3

Strong players blunder less in both, but the jump when ahead is the same. Being ahead makes everyone stop checking what the opponent can do.

Where the 1600s and 2000s pull away

Won after being three pawns ahead (blitz, typical player)Under 800800–11991200–15991600–19992000+
55%55%59%69%79%

Below 1600, players finish just over half their won games. Then it climbs fast. Split the gap between neighboring rating groups, and moves played while clearly ahead account for about a third or more of it at every step (36%, 43%, 39%, 32% in rapid).

Per 100 blitz gamesUnder 800800–11991200–15991600–19992000+
Let a won game slip2622201610
Lost on time while winning4.52.73.13.01.9

Trading down

When players were ahead and traded pieces, they won more often than when they kept pieces on: 64% against 54% under 800, and 84% against 71% at 2000+. That's true at every rating. Some of it is that easier positions are easier to trade in, so it isn't proof that trading wins games. But it agrees with the old advice: when you're ahead, simplify.

The players who finish are the players who fight

Players who fight back from worse positions also convert more of their good ones, even at the same rating. The habit is the same: keep checking, keep playing, in good positions and bad. (More in What's your chess style?)

What to work on

  1. When you're ahead, look at your opponent's best reply before every move. That's the habit that falls away.
  2. Trade when you can, especially queens. Fewer pieces means fewer tricks.
  3. Watch the clock when winning. Losing on time in a won position happens in about 2 to 4 games out of 100.
  4. Finish. If there's a mate or a clean win of material, take it rather than playing "safe" moves that drag on.

In your report: the closing score and the "when you're ahead" finding show how often you finish won games and where your slips cluster once you're ahead, next to players at your rating.

Common questions

How do you win a winning position in chess? Check your opponent's best reply before every move, trade pieces when you can, watch the clock, and take a clean finish when there is one.

Why do I blunder when I'm winning? Everyone does. At every rating, players blunder about two and a half times as often once clearly ahead as in level positions.

Should I trade pieces when I'm ahead? Usually. Players who traded when ahead won 84% of those games at 2000+ against 71% when they kept pieces on, and 64% against 54% under 800. Part of that is that easier positions are easier to trade in.

About these numbers

See how you finish. Your last 200 games from chess.com or Lichess, or a PGN file. Free, no account.

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