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marsncaissa 10 ( +1 | -1 )
Forced Mate? I am sorry but this is one I really don't know. Can a rook and knight force mate against a rook?
kewms 22 ( +1 | -1 )
Um, I think you should probably wait until your game with steveoz (board #7733959) is over to get advice on that question.
marsncaissa 17 ( +1 | -1 )
Not Advice Just a question. I am not asking how to defend or anything. If that question had already been asked and answered here, would it be cheating if I read that thread?
eqj2 12 ( +1 | -1 )
No one can or will give you a answer to your question. You have a active game in which your question pertains to.
marsncaissa 8 ( +1 | -1 )
Fair Enough. Didn't know there was a rule. I guess I will open a book.
More: Chess
heinzkat 34 ( +1 | -1 )
Well, it has been discussed on the GK forums before. I think it is okay to link there
-> gameknot.com

Moreover, there is no board in which there is a R+N vs. R endgame. There are still pawns + a Knight left for both.
Greetings.
marsncaissa 56 ( +1 | -1 )
So there we have it. Turns out that you can have your cake and eat it too.
-> www.shredderchess.com

8/8/5nk1/1R6/4N1r1/4K3/8/8 b - -

steveoz sent me this after I linked him to this thread before the end of our game.

You can indeed answer a question if it is not position specific. right?

Can a king against a king force mate? ;)
kewms 127 ( +1 | -1 )
From the FAQ:

Q21: What is considered cheating? How to report cheaters?

A: It's quite simple -- you can not use anything besides your own brain, and you can not consult anyone besides yourself. That includes chess programs, chess engines or chess computers, your friends, colleagues etc. etc.. Chess books and game/move databases are allowed (as they are permitted in correspondence chess too). Nalimov endgame tablebases, or any other books/programs/tools that show the exact moves to make for a guaranteed win/draw from a given position on the board, are not permitted. Feel free to analyze your games with chess engines or discuss them with your friends after the game is over, but not while the game is still in progress. If you suspect someone is cheating, please contact webmaster with a formal complaint. Don't forget to include specific details of why you think someone is cheating.

***

The Shredder link you posted is a tablebase, containing all possible 3,4,5, and 6 piece endgames. Shredder itself is a chess engine. So neither would be allowed.

Likewise, asking about the theory of R vs R+N endgames when you are in the middle of playing one, or deciding whether to trade into one, sounds like "consulting" to me, hence my original post in this thread.

marsncaissa 54 ( +1 | -1 )
thread closed Thank you kewms. Aside from asking my question, I have not used any other source to decide a move or sequence of moves. Your last post spells out the rule quite clearly and I understand now what exactly it was that I was doing wrong in this thread. You may just have saved my butt and account. Thanks again and let us leave this alone now.
marsncaissa
ionadowman 37 ( +1 | -1 )
But since the game has ended... ... the question - whether, and in what circumstances, and K+R+N defeats a K+R - is now open for a more general discussion. Specifically, the game position diagrammed two or three threads back is a draw with best play. But there may be non-trivial positions in which the stronger side can win (by non-trivial i mean positions in which there is no immediate capture or mate on the move). Any examples?
Cheers,
Ion
ganstaman 72 ( +1 | -1 )
Well, I guess it depends on precisely what 'non-trivial' means. You can set up positions where the stronger side will win the rook eventually, but just because it's a few moves into the future doesn't mean it's exactly difficult (somewhat forced sequences, that is). I tried several times, and I could only get the stronger side to win when the weaker king and rook were near each other, and the stronger pieces were coordinated to set up a fork soon, or when the weaker king was isolated in the corner and almost mated.



Black to move. In 6 moves, white will win the black rook and then mate. Non-trivial? Not sure.
ionadowman 78 ( +1 | -1 )
I call this position "non-trivial"... By "trivial" I meant simply mate on the move or capture on the move ... mentioned for the sake of completeness more than anything. In the above position, White has mate on the move, which would make it a "trivial" position were it White to play. As it is Black to play and he has a possible defence (1...Rg1ch) then White still has some work to do. What does he play: 2.Kh6 or 2.Kf7? My first thought was the former, but it's not so easy 2.Kh6 Rg2 3.Re8ch Rg8 4.Re7 Rf8 etc. OK, then, try 2.Kf7, threatening 3.Rh6mate. 2...Rf1ch 3.Nf6 now threatens 4.Re8mate. Is that the end? Well, no: 3...Re1!! and White can't take 4.Rxe1 owing to the Stalemate! So really we are in endgame study country. I have a feeling this will take longer than 6 moves ganstaman!
Cheers,
Ion
ionadowman 102 ( +1 | -1 )
H'mmm... ... on reflection, I seem to have misread ganstaman's last. For some reason I inferred that it was mate in 6 or something not too different.

Let's review the position: b

Black, to play, has little choice: 1...Ra8 or ...Rg1ch. Let's get rid of the former first: 1...Ra8 2.Nf6 Rd8 (say) 3.Re7 and now it's perhaps not so much "trivial" as "elementary": 3...Rg8ch 4.Nxg8 Kxg8 5.Re8#.
The main line, then, is 1...Rg1ch 2.Kf7 (2.Kh6 seems to draw) 2...Rf1ch (2...Kh7 is the alternate defence) 3.Nf6 Re1!! 4.Ne4 (forced, since any rook move along the 6th rank will be met by the corresponding response e.g. 4.Ra6 Ra1!) 4...Rf1ch ( the other defence is 4...Rh1 5.Re8ch Kh7 6.Nf6ch Kh6 7.Rh8ch winning the Black rook) 5.Kg6 Rf8 (else 5...Rg1ch 6.Ng5 and Black has to give up the rook [6...Rxg5] to stave off the immediate mate) 6.Nf6! Rd8 7.Re7 etc as in the 1...Ra8 line.
What about 1...Rg1ch 2.Kf7 Kh7 then? Try 3.Nf6ch Kh6 4.Ng8ch! Kh5 5.Rh6ch Kg4 6.Rg6ch once again picking up the rook.

No: I would not call the position "trivial" nor even "elementary". There's plenty of play in the 6 moves White requires to secure the mate or a winning material advantage.
Cheers,
Ion



ganstaman 44 ( +1 | -1 )
Hmmmm, I did judge too quickly based on the top line alone. I guess the only thing resembling a point that I could still have -- it's a win only in positions that look won...? In other words, black's king is looking a little trapped there, and that really helps white win. Transplant those pieces to the center of the board and I think it's a draw. Nice work, though. I now have some reading to do :)
ionadowman 65 ( +1 | -1 )
The position we have just discussed... ... is a special case: in general, K+R+N vs K+R is a draw. For instance, suppose instead of 2.Kf7!, White played 2.Kh6? in response to 1...Rg1ch. It seems that White can not win from here, even though the Black king is so confined. Probably the best chance for Black is for the K to break out at once: 2...Kg8 whereupon White has no way of preventing the Black king heading for the open country by 3...Kf7.
In an earlier posting I suggested 2...Rg2 instead, but that loses for Black: 3.Nf4! Rh2ch 4.Kg6 and mate follows quickly. 2...Rg4 by preventing 3.Nf4 might preserve the draw, but I think I would go for 2...Kg8 as the clearer road.
Altogether, the diagrammed position is an unusual case, and even then the road to victory for White is a narrow one.
ccmcacollister 68 ( +1 | -1 )
If ... I had noted that my opponent was admitting publicly to not know whether a position would be winnable vs drawn and I had the 'greater' side... he could be assured of getting to play it out and learn it firsthand, without any qualms on my part. I would consider publication of such a state to be an impassioned plea to be put to it! :))
It would be like saying; "I know nothing of the technique, and so I give you leave to take numerous deep shots at me and see if I can catch them all ..." . But I will always make an opponent play thru a position and "prove" at least once, if there are any doubts about it being new to them. Have always just considered it a point of technique to do so. Or maybe I am just a grumpy-dumpling?!

}8-)
ccmcacollister 25 ( +1 | -1 )
besides ... -I-got put thru it as Expert or nearly so ... and fair is fair, right? And as they say, those who have been abused in the endgame at an early age ... are gonna be grumpy dumplings ... (especially when I realize my opponent was Right to try me on it, for I lived but by the grace of mutual fatigue! )
thunker 5 ( +1 | -1 )
Oh.... The value of keeping one's mouth shut if one is concentrating on a win..... ;-)
ionadowman 40 ( +1 | -1 )
There's nothing ... ... to stop you playing it out to 50 moves anyhow. I once had a K+R vs K+N endgame that I thought was probably drawn, but decided to play on. Instead of going after the King, I went after the knight. It worked!
On one of the occasions I had K+B+N vs K my opponent kept insisting it was a draw. Well, I just had to show him different, didn't I? It is that episode that justifies my playing on if I think there's still play in a position.
ganstaman 45 ( +1 | -1 )
One of my earliest games here I was on the wrong side of a K+R vs K+B endgame. If you play it out with a tablebase you'll see that it's a fairly easy draw (basically: let your king be 'trapped' in the corner opposite colored from your bishop, keep your bishop on a diagonal near your king, and don't put the bishop en prise). My opponent made us play it out for a while.

I eventually won by timeout, though I would have accepted a draw offer at any time.
ionadowman 84 ( +1 | -1 )
Now, that raises an interesting topic! ...Almost worth beginning a new thread on. It seems to me that your opponent timing out in that situation ought to have resulted in a draw, rather than a win for the weaker side. The reason is that the K+B is insufficient to deliver checkmate (try it and see).

But just to complicate the issue, K+N can deliver mate against K+R viz:
b
Does that mean that if K+R times out vs K+N the latter does win?

According to my copy of the "Official Rules of Chess" (FIDE and USCF 1974) a game is drawn if (p.111) 7(f): "...one player has insufficient material for a possible checkmate and his opponent's flag falls first." That does suggest to me that when K+R times out, the result is a draw if the enemy has K+B and a loss if the enemy has K+N.

It is true that the rules might have changed in the last 33 years. Any update on this?
Cheers,
Ion
ganstaman 34 ( +1 | -1 )
I think then that gameknot rules and FIDE rules differ? What about ICCF rules?

Either way, it's entirely my opponent's fault, so I want the win. :) If I had a knight, I could see him testing me (it looked a bit harder to me than with the bishop -- in fact, I had a choice of which one to keep). But the bishop just draws too easily, I think.
heinzkat 5 ( +1 | -1 )
In correspondence chess A timeout means you lose. Even if you have K+Q+Q+Q+Q vs. K.
ionadowman 5 ( +1 | -1 )
Well, you learn something new... ... every day. I didn't know that.
Cheers,
Ion
ccmcacollister 51 ( +1 | -1 )
But ... to expand In the Postal game, you used to have to Overstep timecontrol
Twice before being forfeit ... where time keeping was not so unbiased as online corr. I guess. And a postmark might be missed at mailing, then get cancelled Later. So it might disagree with the claimed Sent Date ... causing an overstep by PostalClerk, since the Official Sent date was held to be the earliest PM date one the postcard. (There was a case of mistaken Cancellation once, where the PostCard arrived before it was Sent !?! :)