If a strong engine (eg. Stockfish) plays with itself many times (say, 100 times), what will be the outcomes in terms of the following:

  1. What will be the proportion of draws? Will there be wins/losses? If so, what could determine wins? Will it tend to be predominantly white (because of opening advantage) or just random?

  2. Will all the games played be along a narrow repertoire? Will there be diversity in games played?

  • 2
    Have you tried setting up an engine match to answer these questions yourself? I'm not a Stockfish user, but Fritz allows engine matches.
    – user1108
    Sep 29, 2017 at 8:43

2 Answers 2



has information on exactly what you want. They are self-playing tests for improving the Stockfish code base.

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The draw rate is roughly about 60% - 70%. There're lots of wins and losses. I believe white has more wins but it's not shown on the page.

Chess engines aren't perfect, they do make mistakes. If SF makes a bad move at move 20, the same algorithm might find the win a move later (21) because it can search deeper and further.


With best settings and same opening moves, the results should be the same every time. Not very interesting. Only variation that might occur is if search depth vary due to time limit and random dips in processing availability.

With different predefined openings white is expected to win up to 6% more often (opening advantage). This might vary from engine to engine and restrictions put on that engine (search depth/time).

If you google it, there have been some Stockfish vs Stockfish games played and most of them seem to end in a draw. But I can't seem to find any extensive statistics.

  • 2
    Lot's of statistics (too many!) in my answer!
    – SmallChess
    Sep 29, 2017 at 13:25
  • 2
    There is some inherent randomness in at least some of the chess engines: chess.stackexchange.com/questions/19482/… Feb 22, 2018 at 19:40
  • 3
    If the results were the same each time, then as soon as someone won once they could just play the same moves and never lose against the engine again (for that color). Feb 23, 2018 at 20:38

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