What is Insufficient Mating Material on this Server?

Okay Okay. Maybe that's what I get for playing around but the server just called my game a draw for "insufficient mating material." I had just promoted to a Knight... my eighth on the board.

So how is the server testing for mating material? Looking for Bishops? It only takes three Knights to force a mate so I had five to spare. Am I the only person who tests this stuff?

And what happens if I get one of those endings that require more than 50 moves to force a mate? Okay I don't know what they are but they must exist because most chess organizations have rules saying if you can prove a forced mate then the 50 move rule is waived. There supposed to be some fancy minor piece mates that require over 200 moves. Urban legend? I thought I read it in Chess Life. I don't even remeber where I heard it from.

But I know how to mate with minor pieces when the other guy doesn't have any. BBKvk BNKvk and NNNKvk. and of course the NNNNNNNNKvk I was setting up.

Time to peer at the code some more.

P.S. The stalemate function seems to work okay.

This game:

http://www.chess.com/echess/game.html?id=76069

is definitely a work of art!  From my experience as a retired computer programmer, I'm guessing that 8 of any piece probably qualifies as 0 (3 bits allocated for number of each piece, and 7 increments to 0).

As for which mates take more than 50 moves: according to Fine and Benko, Basic Chess Endings, p. 271, this can be true for 2 bishops vs. knight.  Don't ask for details!

Another item which I'm curious about but too lazy to test... what about 3 repetitions of position?  My recollection is that this can be demanded as a draw but is not automatic. Does a button appear "Demand Draw" at this point? 

After reviewing the chess library we are using here at chess.com, their draw logic did seem a bit off. I have changed it so that this shouldn't occur any more. Regarding the 50 move rule, we do enforce that in the code as well.

Yes, a button appears. I think it said 'claim draw?' something like that.

What I really want to do is surround a Black King with eight White Knights and then capture Black's last piece to force a stalemate.

Otherwise I want to surround a White King with eight White Knights and then pin them with eight Black Queens for a stalemate.

Is this too much to ask?

Here's another glitch to add to pawnshover's knight puzzle. 

I just had a message from my friend Looby who was mated by a pawn check which he could have avoided by capturing PxP e.p. The computer obviously ended his options when it decided he was in check with nowhere to go and consequently was not entitled to another move. At the time he was a piece up for three pawns and the game may well have gone either way.  It was certainly not mate.

 This game was incorreclty declared as won by checkmate most likely because the logic checking for checkmate does not take en passant capture under consideration when checking all legal moves.

gmatt wrote: Dozy wrote:

Here's another glitch to add to pawnshover's knight puzzle. 

I just had a message from my friend Looby who was mated by a pawn check which he could have avoided by capturing PxP e.p. The computer obviously ended his options when it decided he was in check with nowhere to go and consequently was not entitled to another move. At the time he was a piece up for three pawns and the game may well have gone either way.  It was certainly not mate.

http://www.chess.com/echess/game.html?id=913811

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 This game was incorreclty declared as won by checkmate most likely because the logic checking for checkmate does not take en passant capture under consideration when checking all legal moves.

Do you really think that might be the problem?

gmatt heres another age old riddle only you might be able to solve.

"There are three words in the English language that end in GRY. Two are HUNGRY and ANGRY. The third one everyone uses every day and knows what it stands for. If you listened carefully, I already told you what the word is."

 According to Tim Krabbé, a forced checkmate in 517 has been found during 7-piece tablebase generation. See http://www.xs4all.nl/~timkr/chess2/diary_16.htm

i think maybe king willy is having a lend of us.  after using up all my own limited brainpower i tried an anagram dictionary and a computerised scrabble program and it gives only those two.

come clean, your majesty, if there's a third will you share it with your loyal subjects and stop the pain? 

Hotflow, don't get anGRY with me if you are hunGRY.

Here's the solve. Trust me it's a bit of a let-down. ;-(

http://www.riddlenut.com/gryriddle.php

i suppose we're getting way off topic here but until somebody spanks us i guess it won't matter.

suffering?  you helped me understand how a work friend felt after she'd been setting us riddles (i think she thought she was bilbo baggins and i was gollum when they first met in the hobbit). in retaliation i asked her, "What is the trade of the prime minister?"

when she finally asked for the answer she managed to grind her teeth and scream, both at the same time (a remarkable feat).  but that's how i felt.

so here's your question:  what is the trade of the prime minister?

the answer is two words of 7 letters and 5:    ------- -----

now it's your turn to suffer!