The definition is simple. The game is a draw if a mate could not be achieved by any sequence of legal moves.
You can't achieve mate with a K+N vs king, no matter how stupid your opponent's moves are. However, in a K+R vs K+R, blundering the rook away is a legal move, and so is the mating sequence.
Also, when your opponent has other pieces on the board, even a lone knight might be able to achieve helpmate.
Puchiko, thanks for the reminder. So K+N vs. K+N is not insufficient. But what about the opposite-colored Bishops? Mate can be set up, but I know that some programs will declare the draw by insufficient material as soon as any such material configuration arises:
Well, those programs are not respecting the FIDE rule which is clear: If any sequence of legal moves can lead to mate (and the opposite coloured bishops are a clear example of that), it's never a draw by insufficient material.
I guess these programs are practical, in most of such positions (e.g. K+N vs K+N) playing on is pointless, and the computer doesn't want to bother you with an additional fifty moves just to prove you really aren't going to march right in that corner and do everything you can to lose.
However, it's important to keep in mind that such endgames are still not automatic draws in tournament play.
LOL
While I guess you could force some 3-year-old kid with a 300 FIDE rating to play it out in a tournament, practically everyone else who plays tournament chess won't mate themselves in K+N vs. K+N scenarios.
It is important to keep in mind that such endgames are automatic draws if you facing someone with half a brain, i.e. if they actually played strong enough to get you into a situation where both of you only have a Knight left, then they are more than capable of auto-drawing you.
Definitely good to be aware of. But I also vaguely remember a game between Bobby Fischer and someone else, where all the material was exchanged down to bare Kings, and Fischer played on three more moves before admitting that it was drawn. I don't remember any other details about the game, or whether it was even in a tournament, but I do remember reading about it in an issue of Chess Life a couple years back. The article explained that the game took place many years ago, back when Fischer was young and very headstrong and feisty. So I don't know how credible the account is, but I would hope both FIDE and USCF would not allow that nonsense to happen.
Was this a blitz game? A professional match went all the way to an endgame with K+N vs. K+N with G/40/2 and Sudden Death time controls? Crazy if that happened!
A professional player playing a game under standard time controls, just happened to get flagged in a K+N vs. K+N scenario when she was one move away from a possible help mate? Seems like 1 in a million odds. What was she thinking? Do you have a link to the actual game?
But can't a player, under most circumstances, ask that the time control to be set to something+increment with "insufficient losing chances" to which KNKN certainly counts? And how do you get flagged with an increment? What part of this do I not have right?
LOL
While I guess you could force some 3-year-old kid with a 300 FIDE rating to play it out in a tournament, practically everyone else who plays tournament chess won't mate themselves in K+N vs. K+N scenarios.
It is important to keep in mind that such endgames are automatic draws if you facing someone with half a brain, i.e. if they actually played strong enough to get you into a situation where both of you only have a Knight left, then they are more than capable of auto-drawing you.
Of course that's true-for actually playing out the game. However, the rule has another important function. Imagine you're playing a rapid tournament, they tend to be sudden death. In a K+N vs K+N scenario, the player whose flag falls loses on time: your opponent has sufficient material to mate. If you have a K+R against a lone king, but don't manage to mate before your flag falls, it's a draw, because your opponent couldn't have won by any sequence of legal moves.
As for the Fischer story-that's well known. And it's exactly the reason why the rules are different today.
A while back, I had an live game where my opponent had insufficient material for a mate (lone king) while I had material and was on my way to a mate. Unfortunately I ran out of time before completing the mate. The game was declared a draw since my opponent could not win with a lone king even though he had time left. I always felt I stole that draw. Is that how the rule actually reads?
Added Later: Based on the above I guess that is how the rule reads.
I never knew the rule about running out of time despite the opponent having insufficient material! That is fascinating, and it makes perfect sense.
The famous "insufficient chance to win" rule... a good one to know...
Thoth86
Yeah I suspected it was a blitz game. I think it's just too impossible for it to happen in a match played with professional time controls: you have 3.5 hours on your clock, plus you can think on your opponent's time as well! Players would most likely just agree on a draw.
In blitz, I can see playing on, as even if material is even and it's likely to be a stone-cold draw in regular play, the side winning on time will likely refuse all draw attempts and hope to win on time.
LOL
While I guess you could force some 3-year-old kid with a 300 FIDE rating to play it out in a tournament, practically everyone else who plays tournament chess won't mate themselves in K+N vs. K+N scenarios.
It is important to keep in mind that such endgames are automatic draws if you facing someone with half a brain, i.e. if they actually played strong enough to get you into a situation where both of you only have a Knight left, then they are more than capable of auto-drawing you.
Of course that's true-for actually playing out the game. However, the rule has another important function. Imagine you're playing a rapid tournament, they tend to be sudden death. In a K+N vs K+N scenario, the player whose flag falls loses on time: your opponent has sufficient material to mate. If you have a K+R against a lone king, but don't manage to mate before your flag falls, it's a draw, because your opponent couldn't have won by any sequence of legal moves.
As for the Fischer story-that's well known. And it's exactly the reason why the rules are different today.
No, I am not 100% sure about FIDE, but in USCF, you can claim an automatic draw in K+N vs. K+N even if you only have 1 second left on your clock (provided I guess that you're not in a 1 in a million position like the one Thoth86 posted). I've been told FIDE has a similar rule.
As others have posted, you could claim a draw on two accounts: Insufficient Mating Material AND Insufficient Losing Chances. Maybe FIDE is different?
LOL
While I guess you could force some 3-year-old kid with a 300 FIDE rating to play it out in a tournament, practically everyone else who plays tournament chess won't mate themselves in K+N vs. K+N scenarios.
It is important to keep in mind that such endgames are automatic draws if you facing someone with half a brain, i.e. if they actually played strong enough to get you into a situation where both of you only have a Knight left, then they are more than capable of auto-drawing you.
I differ in your idea. In the example shown of K+N V K+N, the last move of black could be removing a bishop to force draw by insufficient material. But alas, he was mated in K+N V K+N. Such a traps are very much possible in reasonable play.
The examples given of K+N vs. K+N can absolutely be claimed drawn. They will either be agreed drawn or shown to the arbiter. My point, however, is that, thanks to all the well-informed posts, evidently this type of position is not insufficient material. It is a picky thing, admittedly: yes, it's a draw by several methods (agreement or insufficient losing chances, or even threefold or fifty-move, depending on if/how it's played out), but calling it insufficient material is, apparently, incorrect.
The position can be claimed draw and will be agreed to draw, but not after Nxb8
idk, i think if your time runs out with K+N vs K+N you lose. Even if you kave K+R+N+Q vs K+N, if your time runs out, you lose. I know its sad, but I think its the rule. If its possible to helpmate, then you will lose when your time runs out.
I've never played in a blitz tournament, so maybe there if you get flagged then you lose. But in no way should you lose in a rapid/standard tournament with either K+N vs. K+N or K+9Q+2R+2B+2N vs. K+N. If you do, then either you don't know the rules and/or you have a bad TD.
If you have Rook, Queen, and Knight to your opponent's lone Knight in regular tournament match, then you can ALWAYS claim draw due to Insufficient Losing Chances unless you are like 1 move away from what would be a smothered mate heard round the world!
What are all possible material situations where a draw by the insufficient material rule applies? There's...
K vs. K
K vs. K+N
K vs. K+B
But what about K+N vs. K+N? Of course it's a draw in practice, but is it considered insufficient material? By similar logic, K+R vs. K+R would also be agreed drawn, but that is not insufficient material, because if one Rook were to be lost, the other player could easily force mate.
Also, what about K+B vs. K+B with opposite-colored Bishops? And are there any other scenarios where the material on the board would be insufficient to force mate from that point until the rest of the game?