Why is this a draw?

Hey everyone!

I have an interesting question.

I was black in this position, and my opponent ran out of time. It is a draw - time out vs insufficient material.

I just have one question: why didn't I win? It is possible to mate with a lone knight, if the enemy king is in the corner, blocked by his own pawn.

This case resembles the Carlsen-Firouzja blitz game in 2020, when Carlsen won on time despite having only a bishop...

So, what are your thoughts?

Probably due to programming constraints, Chess.com doesn't recognize the possibility of "helpmates".   

Chess.com rule. They (sadly) do not follow Fide rules. Read more:  https://support.chess.com/article/128-what-does-insufficient-mating-material-mean

We discussed this question yesterday, link: https://www.chess.com/forum/view/more-puzzles/my-favorite-simple-chess-puzzle-few-pieces-hard-puzzle#comment-57221532 

Actually this question is asked every few weeks so you will find the answer many times on chess.com. In short: chess.com gives you a draw contrary to what the FIDE rules say. Insufficient mating material is only recognized by USCF competition rules.

I think to some extent that also reflects FIDE's Artical 10 Quickplay finish rule where when it is not possible to win by normal means (checkmate) the opponent can claim a drawn.

Good point! The rules we addressed are algorithmic, i.e. executable by a machine. To determine "normal means" one requires a human arbiter.

best

A lone knight couldn't win. It has to be "helped" with some other piece.

I raised this issue in the following thread: https://www.chess.com/forum/view/general/black-ran-out-of-time-is-this-a-draw

The site is an American based platform and so it follows the USCF rules, which in my opinion is COMPLETELY wrong as using the rules of a National Federation on an international platform doesn't make sense.

It doesn't quite follow US Chess rules.  In US Chess if the K+B or K+N have a forced mate then the flagging player still loses (in post 11 if the White knight was on f1 and the Black pawn was on h3 with Black to move then in chess.com Black could deliberately flag to get a draw instead of playing the forced h2, while US Chess would see that the forced h2 allowed Ng3# and Black would still lose after flagging).  FIDE and US Chess have gone back and forth on various rules over the years with US Chess sometimes changing a rule to match FIDE and then FIDE switching to the rules US Chess moved away from.

Both FIDE and US Chess have rules that you cannot win on time if you cannot win by any legal sequence of moves.  An example would be White having Pa4, Pc4, Pe4, Pg4, Bf3, Ke2 with Black having Pa5, Pc5, Pe5, Pg5, Bf6, Ke7.  In that position both US Chess and FIDE was award a draw after a flag (well, both would also allow the arbiter/TD to declare a draw before either player flagged).  Chess.com however would assign a loss to a player that flagged because only material is looked at, not the position.

Works with a Bishop too

Chess.com is based in the USA, and it follows USCF (United States Chess Federation) rules on "Insufficient Material", not FIDE rules.

USCF 14E.

Almost follows.  There are positions where 14E would award a win on time and Chess.com would award a draw.  There are positions where 14E would award a draw and Chess.com would award a win on time.

Chess.com is not a MAGA website but an international one. None of its activities and tournaments come under the USCF umbrella and I am sure chess.com would love to follow the FIDE rules. The only problem is that they can't - like nobody can. A full proof one- or two-sided "dead position" tester is hard to build and their current rules are just a practical compromise. It may take some decades yet before we have a good algorithm to plug into SF and its friends.

The US(CF) has chosen the worst of all evils. The FIDE rule is crystal clear, fewer exceptions. 

If you time out with a whole army against a lone pawn - how does he win without help, mate? Is this an US draw as well?

The whole world consider the rule-set unprofessional, even a kindergarten.

<A> The US Chess cited giving a draw after the opponent flags is only for K vs any, K+B vs any (if there is no forced win), K+N vs any (if there is no forced win), K+2N vs any without a pawn (if there is no forced win).  K+P(or more), K+R(or more), K+Q(or more), K+2B(or more), K+N+B(or more) and K+2N vs K+P(or more) are wins if the opponent flags regardless of the opponent's pieces.  The K+N, K+B and K+2N are the variation from FIDE.

<B> There is an additional rule that gives a draw if there is no legal way to reach mate even when there is a lot more material (that matches FIDE).

Chess.com has chosen a less exact version of the US Chess rule that gives more K+B. K+N and K+2N draws than US Chess would, and which gives more additional material wins than either US Chess or FIDE would.

For Chess.com to match either US Chess or FIDE it would have to be able to calculate whether or not a position was one where any checkmate by the non-flagging player was impossible (such as K+4P+B vs K+4P+B where the pawns are blocked, the kings are locked behind the pawns and all pawns are on the opposite colored squares from the opponent's bishop).  If it ever reached the point where that calculation could be done then the FIDE rule could be applied (and thus avoid the further step of looking at K+N, K+B and K+2N positions to see if there was a forced mate to satisfy the US Chess rule).

There is a way of implementing part A of the FIDE rule and continuing to award part B wins that that neither FIDE nor US Chess would give.  That would be for K+2N to be winning material regardless of the opponent's material, for K+N to be winning material if the opponent had at least one piece besides the king and any number of queens, and for K+B to be winning material if the opponent had at least one of: pawn; knight; bishop of the opposite color. (any pawn would suffice for K+B or K+N because a pawn can be promoted to a knight and thus allow for a helpmate).

People can lobby for Chess.com to implement a watered-down variation of FIDE rules but it would take a much more involved task to try to implement the actual FIDE rules.

Simplest example of a difference between FIDE/US Chess and Chess.com

White Ke1, Qe2.  Black Ke8, Qe7.  If one player plays QxQ+ and the other player flags before making the absolutely forced KxQ capture then FIDE and US Chess will rule it a draw (no series of legal moves leading to checkmate) while Chess.com will rule it a win for the K+Q since K+Q is mating material.

I didn’t understand you.