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| Posted by tugger uskidscompute.com 8/09/2006 08:12:55 play online chess |  Subject: K+N+N vs KMessage: here is a mate for those who are unaware... but can white force black into this position? |
| Posted by johnrowell uskidscompute.com 8/09/2006 08:28:29 play online chess | No Message: It's bad enough trying to force a K+B+N v K victory! |
| Posted by chuckventimiglia uskidscompute.com 8/09/2006 08:29:40 play online chess | Tugger go to..... Message: the minimum pieces to checkmate are K+B+N not K+N+N I know you can set up a board like you did but I do not think a mate is possible in a real game. I think it is a forced Draw. |
| Posted by lucasbeauchamp uskidscompute.com 8/09/2006 09:06:12 play online chess | Let's work backwards Message: Now, if there had been a bishop on e8, the king could have been forced to play Kf7Xe8, but that's not KNN vs K, is it. |
| Posted by chuckventimiglia uskidscompute.com 8/09/2006 09:23:02 play online chess | Go ahead and set up the.... Message: Start with K+N+N vs a K Tell Fritz to move. Fritz will move then offer a Draw. Refuse the Draw. They will move 3 more times and it ends in a threefold repetition. Fritz cannot win because it knows it is a Draw. Try it!! |
| Posted by tugger uskidscompute.com 8/09/2006 11:04:58 play online chess | Message: working backwards from a position does appear to be the best way to see if it is forcable... i now know for future reference not to allow a game to get to K+N+N vs K if i'm up, or to attempt to encourage it if i'm losing... |
| Posted by ganstaman uskidscompute.com 8/09/2006 12:49:54 play online chess | Message: Here, this may be better: -> en.wikipedia.org . I know I've read a better article on this somewhere, but this is the best I can find for now. |
| Posted by ionadowman uskidscompute.com 8/09/2006 13:06:20 play online chess | But check this out: Message: White to play and win (mate in about 9, I think). (I composed this little puzzle one idle afternoon a few years ago...) Cheers, Ion |
| Posted by ionadowman uskidscompute.com 8/10/2006 13:53:32 play online chess | No takers...? Message: Actually, 1.Nd6 is equally good... Cheers, Ion |
| Posted by ionadowman uskidscompute.com 8/11/2006 00:37:14 play online chess | The thought occurs... Message: The idea led me to compose this little puzzle: w White to play and win. Sure White will win anyhow by picking up the a=pawn, then driving the BK into the h1 or a8 corner. Or he can cut to the chase by getting rid of the bishop: 1.Bd5 a3 (forced) 2.Ba2!! Kxa2 (forced) 3.Ne2 Ka1 (forced) 4.Nc1 a2 (forced 5.Nb3 checkmate. A forced win by K+N vs K+P. |
| Posted by tugger uskidscompute.com 8/11/2006 16:16:59 play online chess | Message: here's a puzzle for you then... white to play and win (a1 is bottom left)... black can hold out for 21 moves min, 23 max... white mates with just one bishop and the king... if you want to know the answer, or be able to move the pieces, it's puzzle #1006, which can be found here... -> gameknot.com |
| Posted by ionadowman uskidscompute.com 8/11/2006 18:58:00 play online chess | Very neat, tugger... Message: Cheers, Ion |
| Posted by ionadowman uskidscompute.com 8/11/2006 18:58:24 play online chess | Very neat, tugger... Message: Cheers, Ion |
| Posted by cjjpeterson uskidscompute.com 8/11/2006 19:05:20 play online chess | puzzle not there Message: cjjpeterson |
| Posted by ionadowman uskidscompute.com 8/11/2006 19:41:07 play online chess | Odd... Message: Sorry about the double posting, by the way. Absentmindedness... |
| Posted by tugger uskidscompute.com 8/12/2006 06:33:11 play online chess | Message: cjjpeterson... if you voted for it, it will disappear unless you click 'show all'... |
| Posted by ionadowman uskidscompute.com 8/12/2006 13:48:46 play online chess | tugger... Message: I do quite like endgame study as such, tho' I don't do all that much of it unless something, like the K+N vs K+P idea, intrigues me. I have been very fortunate in my more recent games to have had some very interesting endgames, well worth devoting time to! Cheers, Ion |
| Posted by ionadowman uskidscompute.com 8/13/2006 14:17:03 play online chess | Here's a curly one... Message: First of all, is such a thing feasible? After a bit of thought, I came up with this: w The sequence goes: 1.Re8+ Qxe8 2.Qxe8+ Kxe8 with a view to... 3.Nf6# OK it's feasible. Is it a win to White, or a draw? White wins. It turns out there is a straightforward answer. The Laws of Chess do not recognise "insufficient material" as a ground for claiming a draw! Seriously. If you think about it, "insufficient material" is really subsumed in the "50-move" rule, since it is very clear that if one doesn't have sufficient material to win at all, one ain't going to do it in 50 moves. Ordinarily, the K+N+N vs K will indeed fail to win in 50. But after Black's 2nd in the above scenario, White requires just 1 move to finish Black off. Cheers, Ion |
| Posted by chuckventimiglia uskidscompute.com 8/13/2006 17:45:40 play online chess | In US Chess Federation OTB..... Message: with the K can ask the TD to adjudicate a Draw and he will honor that request. It is a technical Draw!! I am a TD for the US Chess Federation [not very long] and I had to check with other TDs to make sure. The request for an adjudicated Draw will be granted!! Chuck |
| Posted by ionadowman uskidscompute.com 8/13/2006 19:09:56 play online chess | I am surprised at this! Message: However, that isn't the reason for my posting. Suddenly it occurred to me that my last diagram doesn't work, simply because the BK in in check! The position is illegal, since it has been stipulated that it's White to play. Is the scenario, that after a series of exchanges white is left with a mate-in-one with just the K+N+N against a lone K, the problem is that we are dealing with Knights, and their idiosyncratic moves. For a while it was beginning to look impossible, but then... w Yep: 3 White Knights. Sometime earlier, White found it expedient to underpromote. Now at least, White to play with Black not in check! 1.Nf4-g6+ Qg1Xg6 2.Nf4Xg6# It doesn't seem possible without White has 3 knights, and even then, the material situation occurs only with the delivery of mate. I'm fairly sure that's not a draw! So it appears that K+N+N vs K is inevitably a draw, unless it is already checkmate, on the grounds that any position, any material situation, and any sequence of moves that will yield eventually to a forced mate by K+N+N vs K on an otherwise empty board, will always be delivered by knight capturing and delivering mate at the same time. chuckventimiglia is right. :-) |
| Posted by lucasbeauchamp uskidscompute.com 8/14/2006 08:55:53 play online chess | USCF Rule 14E3 Message: Rule 14E considers several cases where one player exceeds the time limit, and the other lacks sufficient material to win. Even in this situation--the only part of Rule 14, the Drawn Game that considers KNN vs K--a mate in one is covered by the language "forced win". ionadowan: yes, the rules have changed since 1974. However, they have not become absurd. chuckventimiglia: TDs may adjudicate a draw, but if they do so, they must be within the rules. If they adjudicate a forced win as a draw, they will be in error. However, as black is already in check when white moves in the position given above, we would need to check the scoresheets, and restore the game to a legal position. If that is impossible because of the condition of the scoresheets, a draw would be the appropriate result. C'mon folks. Black is in check and it is white's move?? |
| Posted by ionadowman uskidscompute.com 8/14/2006 14:27:52 play online chess | lucasbeauchamp... Message: This is the sort of position we are discussing: If it is Black to play here, he escapes into the open, and it is indeed a draw. If White to play, Black must have played ...Ke8, from one of 3 possible squares. In particular, if the previous position was not a 'book draw', that ...Ke8 had in fact to be ...Kxe8. So, lets emend my 'wrong diagram' a bit: w The Black K is not in check, no one is claiming a draw here, Black is 'doing a Custer', White to play. White plays to the gallery: 1.Qe8+ Kxe8 Can Black claim a draw here? There are 2 considerations. 1. You can claim a draw only in your own turn. He would have to make the claim before he completes his turn, which means, after the capture, but before pressing his clock. If he does complete his turn, he can lodge no claim. 2. The 50-move rule. No one has refuted this argument yet, although chuckventimiglia expressed a different opinion. Since he is more expert in this field than I am, his view is persuasive. But... I am told there have been a number of revisions to the USCF, FIDE and other editions of the Chess Laws, but have any of these rewritings since 1974 added an "insufficient material" clause to the articles on drawn games? If not, on what grounds other than the 50-move rule can a draw then be claimed, here? To be sure, only a complete and utter snurge would insist on playing out the 50 moves in these circumstances! 2.Nf6# White wins. [If you want absurdity, check this out. w 1.Nf8+ Kh8 ... and now, leaving his clock running (so his move is not complete), claims a draw by Stalemate. Is this analogous to a draw claim in the K+N+N vs K situation we have been discussing? If it isn't it comes damned close!] Cheers, Ion |
| Posted by ganstaman uskidscompute.com 8/14/2006 14:34:58 play online chess | Message: Also, the idea of insufficient material is position dependent. That is, 2 knights are often insufficient for mate. But if they can clearly force a mate in the given position, then clearly they are sufficient for mate. Again, the TD can't and won't give a ruling that contradicts the result that would appear on the board without him. |
| Posted by cjjpeterson uskidscompute.com 8/14/2006 14:53:10 play online chess | unless... Message: |
| Posted by kewms uskidscompute.com 8/14/2006 22:08:15 play online chess | Message: All references below are to the 4th Edition USCF rules, effective 1/1/1994. Does anyone know if this is the most recent edition? (And why the heck aren't the official rules on the web, anyway?) Rule 14D covers situations with insufficient material to continue, where the game is instantly drawn because neither side can win. These situations are: K vs K K vs K + N or B K + B vs K + B, with bishops on same color diagonals. "No legal moves that could lead to the player being checkmated." (No examples given, but K vs K + 2N can reach a checkmate through legal moves. One example might be a queen ending with mutual stalemate.) Rule 14E covers situations with insufficient material to win on time. These are NOT instantly drawn. Rather, in these situations a player who would otherwise lose on time saves the draw because his *opponent* doesn't have sufficient material. Material the player has is mostly irrelevant. They are: Opponent has lone K. Opponent has only K + N or K + B, and does not have a forced win Opponent has only K + 2N, player has no pawns, and opponent does not have a forced win. That "forced win" part covers the positions discussed here. If *your* flag falls when your opponent has K + 2N, you get a draw unless he can demonstrate a forced mate. If *his* flag falls, you get a draw because you (lone king) don't have winning material. In all other situations, the 50-move rule applies. (See rule 14F) So yes, that means your opponent can spend 50 moves in a theoretically hopeless quest to force mate with two knights. A mating position exists. And let's face it, a player weak enough to be down two knights against someone who *doesn't* know that two knights is a draw is probably weak enough to stumble into the mate. So the game continues. If both players agree that material is insufficient, or that stalemate exists, then they have agreed to a draw. This instantly ends the game, regardless of the actual position on the board. (See rule 14B) Katherine |
| Posted by fmgaijin uskidscompute.com 8/14/2006 23:34:13 play online chess | IMHO . . . Message: |
| Posted by ionadowman uskidscompute.com 8/15/2006 03:56:13 play online chess | Thanks, Katherine... Message: :-) Ion |
| Posted by lucasbeauchamp uskidscompute.com 8/15/2006 07:52:26 play online chess | USCF Rules Message: ionadowman. My eyes must have been groggy when I read your second long post because I read it without noticing that you acknowledge the illegal position. Sorry. |
| Posted by ionadowman uskidscompute.com 8/15/2006 13:07:08 play online chess | lucasbeauchamp... Message: Your remark that draw claims are now considered to be draw offers is a pertinent one, I think. I wondered earlier if we needed to be clear whether we needed to draw a distinction between offers and claims, since there appeared to be a difference in the way they were handled that might impact on our discussion. It seems the rule writers have been here before! Treating them as indistinguishable simplifies matters. Cheers, Ion |
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