8

I played a game at chess.com and the endgame was KNN vs KP. When the pawn was captured, the server automatically give a draw due to "insufficient material". I am confused about chess.com's insufficient material standard here:

  1. If "insufficient material" means neither player could possibly give checkmate by a series of legal moves, then KNN vs K should not be draw by insufficient material as checkmate is still theoretically possible.
  2. If "insufficient material" means checkmate cannot be forced, then with some rare exceptions, the server should give draws to almost all KR vs KR or KQ vs KQ games, which I have never observed. Similarly by the same principle, many KP vs K game will be automatically terminated as a draw once a drawing position is reached.

So what is the standard here?

| improve this question | | | | |
15

Well, simply put, they chose to follow the USCF "Article 14: The Drawn Game rule 14E: Insufficient material to win on time, 14E3: King and two knights."

While it is not a forced mate, there is a mating position that is possible, thus they could have easily followed the FIDE rule, and allowed the side with the knights to continue playing.

It was probably a judgment call, and one that was made so more players would not be put off by having to play easily drawn positions for 50 moves.

I do not know if it is coincidence that you asked this today, but in the 2019 World Blitz Championship just this morning, there was a big to-do concerning Magnus Carlsen and Alireza Firouzja.

The game was up and down, but then Alireza Firouzja had a winning advantage, but in the final position below, the position was theoretically drawn when Alireza Firouzja knocked a piece over, and while resetting it, he flagged. Should it be a draw since Magnus had no pawns, or a win because there is a possible mating position? Well, after an appeal, and the rules were clear, the game was awarded to Magnus.

Here is the final position, and I will show a sample line, no matter how far fetched, that shows the rule in action. THESE MOVES WERE NOT PLAYED.

 [FEN "8/4k3/4P3/3B2P1/4P1K1/8/3b4/8 w - - 0 1"]

 1. Kh5 Bc3 2. Kh6 Bd2 3. Kh7 Bxg5 4. Kh8 Kf8 5. e7+ Bxe7 6. Bg8 Bg5 7. Bh7 Bf6#

The fact that this is even possible, no matter how unlikely, is why Alireza Firouzja lost under the rules. Although this is an unfair example of the rules working badly in a given position, they have to be consistent, and there may be other positions that would not be so unfair. it would be hard in practice to say, "this is OK here, but not there". They have existed in the past, but rules for different positions (like extending the 50-move rule to 100 moves for certain positions) have never worked well.

| improve this answer | | | | |
  • Please note that in Blitz competitions time rules can often be different. While in a long game someone with a decisive winning advantage but low on time might appeal to the arbiter to award a draw, in a Blitz it's different. – vsz Dec 31 '19 at 13:40
8

The rules applied on chess.com are explained here. Basically the rule says that if there are no pawns and the material is insufficient to force a mate on the lone king, then the game is declared a draw.

This is contrary to FIDE rules and leads to some positions that are actually winning by force being declared draws, as noted here by Nigel Short. Actually, KNN vs KP with the pawn blocked far away from promotion square is one example; it is a win but will be declared a draw if the side with the pawn flags. I guess the reason the online servers adopt these rules is that these positions are very rare, and flagging e. g. with one minor piece each would be quite common if allowed (and very ugly).

| improve this answer | | | | |
  • Thank you! For “material is insufficient to force a mate on the lone king”, how about a drawing position in KP vs K endgame? I do not think the system will give a draw automatically. – Zuriel Dec 30 '19 at 22:31
  • 2
    @Zuriel, I omitted the provision that there must be no pawns. I edited the answer now. – Kostya_I Dec 30 '19 at 22:33
1

Because you cannot mate with KNN vs K but you can mate, in certain positions, with KNN vs K&P, the game was a draw as soon as you took the pawn.

Lesson: If you have KNN let them keep at least one pawn, preferably one close to their 2nd rank and also the edge of the board.

| improve this answer | | | | |
  • You mean, KNN vs K&P? – Zuriel Dec 31 '19 at 0:13
  • Edited; KNN vs K&P has possibility of mate //// KNN vs K is a DRAW. – yobamamama Dec 31 '19 at 0:45
1

Unless the opponent has at least one pawn (in KNN vs K), you are not able to reach checkmate because stalemate should occur first. This is the reason that the position is a draw.

However, in KNN vs KP or KNN vs KPP, for example, there is some possibility that the pawn can take away moves from its own King. This is why the checkmate can sometimes be forced.

| improve this answer | | | | |
  • 1
    As I understand it, it's not usually because the pawn takes away moves - it's because the ability to move the pawn removes some stalemate possibilities. – D M Jan 1 at 6:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.