13

Chess.com has a function called "premove". When pre-moves are enabled, while it’s the opponent’s turn you can make a move to automatically be played as soon as they make their move. The premove will play automatically even your opponent does something unexpected. If your opponent's move makes your pre-move illegal (such as putting your king in check), then your pre-move will be canceled).

My question is, under what circumstance should I use the premove function? I can think of the following scenarios:

  1. My opponent has only one legal move. In this case, if I can determine my reply to this move, I may consider making a premove.
  2. When I am in a very safe endgame (for example, KR vs KB, where I will not lose even after blunders by my rook) and I am running out of time.
  3. In the early opening stage of a blitz game, when my opponent has only one reasonable move and for most of his "unreasonable" moves, my premove is still a good reply. For example, after 1. e4 c6, 2. d4, as white I can more or less safely assume black will play 2... d5 and (pre)play 3. Nc3 before black makes his second move. Even if black played 2... g6 or 2... d6 or 2... Na6, 3. Nc3 is still a sound reply.

Why is there such a function "premove" in the first place? What is the "best" way to make the most of this function?

14

I think case 4: Your premove is illegal unless your opponent does something very specific but entirely expected, is the most common case that I've seen. Like you offering a trade, and regardless of what they take with (including if there is only one way they can take), there is only one specific way you want to take back.

As an example, IM and chess streamer Eric Rosen, when he gets to play the Stafford gambit as black (1. e4 e5, 2. Nf3 Nf6, 3. Nxe5), he always plays 3. ...Nc6, then premoves 4. ...dxc6. Because if that capture is legal, it must be because the white knight captured the black one, and in that case he always wants to take back with the d-pawn.

Also notable example of useful premove (and the converse of case 4, more akin to your case 2) was a drawn endgame where Carlsen had the black pieces during this his 2020 online tour (can't remember which game, or the exact piece placemens, sadly, but I believe it was KQP or KQ versus KRP). He had established a fortress and could premove his rook back and forth between two squares on the sixth rank. The only cases where such a move would lose the game were cases where performing that rook move would be illegal. He had only seconds left and no increment, so he couldn't wait and see what move his opponent would make.

12

Since premove takes very little time (0.1 sec on chess.com) or no time (on lichess.org), they are mostly used in situations when players have very little time: in games with very short time control 3 min or 1 min or shorter!?, or in time scramble in games with no increment or very small increments.

I would be careful with using premove for case 3), in very short time controls, 1 min or less, people can try to trick you, for example if you just played ...g6, they can play Bh6 hoping that you premoved ...Bg7.

EDIT:

There is another use for premove: Set a trap, and premove the "bait" move. People are a lot more likely to fall for it, thinking it is just a premove mess up. Eric Rosen gives a very good example: https://www.youtube.com/watch?v=oksV18QmCwo

  • 7
    Note that on chess.com, a premove does take some time, but only 0.1 seconds (on lichess, it takes no time, so you can play out a whole game with 0.01s on the clock). – phihag Oct 20 '20 at 10:43
  • 1
    @phihag, Thank you, I updated my answer to include this information. – Akavall Oct 20 '20 at 21:55
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Time left on the clock is the main factor determining whether a premove will be worth it or not. You should only do premoves when you are low on time.

Scenario 1 is great for premoves. In scneario 2 you should try to trade your rook for the bishop as fast as possible if you can't win. Scenario 3 is bad for premoves. I've seen so many Bullet games go 1.d4 Nf6 2.Nf3 g6 3.Bh6 Bg7.

Also note that if your premove turns out to be an illegal move it will be cancelled, so you may want to use it for recaptures. For example, if you have a knihgt on d5 protected y a bishop on c4, you can premove Bxd5 to be played instantly if the knight gets captured.

6

If you play without any increment (that I really hate), then sometimes premove is necessary, eg you have 3 sec left in a KQ vs KP ending.

Apart from that, the only time I use premove for is when I offer a trade and premove a retake. So that if they refuse the trade, the premove is illegal and cancelled.

3

You listed a lot of the main uses for a premove. I completely agree with point 1. For point 2, even if blundering the rook won't lose the game in a K+R vs K, you still want to win and not draw. After all, if you don't want to win, why not let your clock run out? It'll be a draw due to a lack of mating material for your opponent. So when you're premoving in this situation, try to make it so that your rook is always protected by the king, or far away. In either of these cases, the rook should check the opponent's king or control squares around it, in order to prevent your opponent's premoves from always being legal (forcing them to manually move). Alternatively, you could try boxing the enemy king in, with the case of your king always protecting your rook, with the goal of actually checkmating and not winning on time. Which way you play depends on how much time both sides have.

For point 3, it's a bit debatable. If all of your opponent's unexpected moves don't cost you material (or something worse), then go ahead and premove. But if there are a few that would be bad, it's more a matter of taste. E.g., after 1.d4 Nf6 2.c4 g6, would you premove 3...Bg7? Sure you save a bit of time, but you're going to lose a bishop in the case of 3.Bh6 (I see a few other answers have included this example too). Meanwhile, in the position after 3.Nc3 Bg7, it would be completely fine to premove 4...0-0. There's no move White has that would give them a winning position against this.

Another good strategy is to always premove recapturing a piece that could be taken (assuming it would be best to recapture it). If the piece is captured, you've saved time; meanwhile, if the piece isn't captured, the premove won't happen and you've lost nothing. The slight downside is that the board might show a preview of your premove while you're waiting for your opponent to move, which could make it a bit harder to calculate. This isn't a big deal though, and on Lichess they don't do this.

On the other side, let's say you're trying to exploit the fact that your opponent is premoving. If they've played the last many moves pretty fast (like premove fast), you could consider trying a dirty trick, like the 3.Bh6 move. This involves getting a feel of how fast they're playing though, since if you tried something like 3.Bh6, your confidence level should probably be at least 50% (if their rating is around yours). It's also rather unsportsmanlike, so it depends on whether you care about being nice or winning as much as possible.

-1

Premoves should only be used if the move is illegal if not for a very specific move the other player makes. An example would be

e4 e5
Nf3 Nf6
Nxe5 Nc6

Here black can premove dxc6 because it will only be legal if white’s move is Nxc6.

Another reason would be if you are low on time, as the other answers so aptly described.

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