When playing online, you have the option to premove (enter the next move, before it is your turn). I am wondering whether there are (generally useful, not contrived) situations where say you have 20 moves to mate with perfect play, but with little time you might be better off going for a longer mate in 30 moves which you can largely premove.

As an example: For the simple endgame rook+king vs bare king, I am aware of two techniques:

  1. gradually decreasing the available space for the enemy king in both horizontal and vertical directions. This can be done without giving check and requires the king to protect the rook most of the time
  2. gradually decreasing the available space for the enemy king in one direction only (horizontal or vertical) by giving check from the side when the kings are in opposition

I believe the first method is quicker, however the second might be easier to premove (not sure).


Almost always the 30 move option is better. There are 2 key reasons: - You only lose 0.1 seconds per premove (on most servers), compared to 0.5 - 1.0 seconds. - Your opponent loses more time since you limit their thinking period by moving instantly.

In my opinion, this is the primary reason why a situation like K+R vs K largely favors the K+R player in bullet. The side with the K+R can always premove, since the lone King cannot create any threats/checks/etc. Meanwhile, the lone King often fails in premoving because the Rook controls squares/gives checks/etc.

If you're slightly lower on time in a sudden death game (say 15 seconds to 20 seconds), you could win just by premoving with the Rook, and trying to purposefully disturb the enemy King. If your opponent can only premove half the time, that's a whole 0.9 seconds they're losing every move. In 10 moves they have lost around 5 seconds (assuming only a 50% success rate in premoving), while you've lost 1 second.

However, if the time gap is more significant (5 seconds to 20 seconds, for example), premoving is not enough on its own. The trick is to premove while slowly trapping the enemy King. The strategy of how you box the King is irrelevant, since time in the key. As long as you premove every move and gradually push the King to one of the sides, it can be enough to win the game. By premoving each move, you're essentially turning 5 seconds into 50 moves.

However, only experienced bullet players (2300+) can premove every move while always making real progress. Thus, it wouldn't be uncommon to see a 2300 blow a win in a K+R vs K with only 5 seconds against 20 seconds.

The key is always premove and try to make some kind of progress; don't worry about the technique you use to box the King.

  • Some servers like lichess don't even have premove costs, which favors even more your argument. – Isac Feb 2 '18 at 0:22

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