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ccmcacollister 119 ( +1 | -1 )
Sac'g the Queen, or other bits & pieces ... Last month I had three Queen sacs. Thought it interesting that only one of the three was a sac to mate. That's the blitz game I cant seem to find. But would like to show the other two from GK corr play. I particularly like the one that sac'd the Q defensively to obtain a pawn down "won" ending. Well I thought it was Won at the time. Now I see a move for better resistance. The other is also for liquidation to a win, removing counterplay fromthe position, that might wither wise have gotten a bit sticky. So I will put those two in this thread after bit.
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Right now I would like to invite anyone else to show there game(s) here involving sacrifice(s) of material. Whether speculative (I love a good Spec Sac!) or forcing a win, or being on the defending side too. Of course, annotation is especially welcome, to any extent you wish. Or without if you prefer.
I like to dispell the myth some people have that Corr Chess tends to be boring. Contrarily, I found my rate of sac involving games would run from 62 to 72% back when I played a lot.
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I havent checked out that rate here at GK, but might be interesting for you to do for yours, and see if you are surprised. :)
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Regards, Craig A.C. }8-)
ccmcacollister 38 ( +1 | -1 )
also ... I found that tugger had a Chess problem listed here on GK that had a real nice Q
sac involved in it too. You might want to check that out.
If someone does find it before I do, would you be kind enough to try to hyperlink it too here. Otherwise it will take me some time, as it was several months ago.
ccmcacollister 261 ( +1 | -1 )
The first Q-sac for a pawn, superficially. Ultimately ending as yeilding of a Rook. I found the game interesting to play, and part of a small experiment (of which the next Q-sac game is as well, strangely enough. Hmmm, wonder if there is something to it!?! ) towards
attempting to stifle counter-play upon the opponents main field of play before embarking upon my own ventures, misbegotten or otherwise.
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In this particular game, I was aware of his potential B-sac upon my kingside and actually offered a draw the move before he did it, on the basis that I felt who ever got adventurous upon their side of the board would probably lose. And that I didnt think he could infiltrate anytime soon without the B-sac ... but he did it. Which certainly does tear open my King position, and is deadly if I "let" his Q infiltrate near my King. He may well win a Rook, certainly win 'enough' back and still have me on the run. So to forego all that ... Qxb2+ !?
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I did look at other moves there such as Bb5 or Ba3 I believe it was, with sac intents there. And tries to gain a tempo before this Q-sac. But in the end I felt the pawn down ending I went into was a winner. Well, um ... sort of.
It did win in the end. But he had a stronger play of 37.Bd3!, instead of 37.e5?! As Bd3 is really a rather "natural" type move, it seems to me perhaps he was simply still in "middlegame mode" mentally, and had not yet shifted gears to Endgame thinking. A common enough phenomenon in the 'heat of battle', as they say. Even GM's do it. But it is one of the things to watch for that can bring victory or defeat.
In any case, perhaps the game is not quite so 'won' after this. At least the chances are better for him and a-pawn has to be watched closely lest it run.
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Even after that, at a glance, he might have interesting chances to mix it up a bit longer on 38. with Bc4 instead of Rxe5. In this and the previous B move, his a-pawn may have the chance to become a real factor.
But after ...Rxa4 /Rxa4 Nxa4 ... I believe it is a definate loss for WT, by about 1 tempo. He has many interesting tries to hold, including the piece sac he made to get me down to one pawn, which is forced and I have no doubt it was intended, after retreating his N where he did.
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This and other tries for WT are quite interesting if one is into endgames. I had to study up on B+N mates for the game. Even so, as long as I have the piece advantage and can get his pawns off while maintaining one of mine,
it can actually be forced in for a Queen by using my pieces to drive his piece and to shield my pawn, as needed. Which is rather long and involved but doeable.
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I wont go into any more analysis unless someone is interested and has some question on it.

-> gameknot.com
ccmcacollister 8 ( +1 | -1 )
correction ... "At least the chances are better for him " ... Better than in the actual game I mean.
ionadowman 216 ( +1 | -1 )
Nice game, Craig... I just played through it quickly, but it does seem that 37.e5 was an oversight. One of those classic opposite castling games... I've never cottoned to the Czech Benoni, myself, and you seemed to hovering on the edge of disaster early on!
I can't seem to arrange Q-sacs in my games - but several of my recent games feature minor sacrifices to reach a favourable ending, or within the ending itself. I've had quite a few 'asymmetric' endgames with a piece vs pawns - always interesting; always difficult. One game still going I entered the ending a pawn ahead (R+B+4P vs R+B+3P, but sacced 2 of them to advance well into the enemy half of the board. He's fought that attack off, but at a cost...
Here's one played a few months ago on GK. You might find it amusing...:
White: zyla
Black: ionadowman
1.d4 Nf6 2.c4 c5 3.Nf3 cxd4 4.Nxd4 e5 5.Nf3 Nc6 6.Nc3 Bb4 7.Bd2 O-O 8.a3 Bxc3
9.Bxc3 Ne4 (We've long since departed from any theory I know of....) 10.Qc2 Nxc3 11.Qxc3 d5 12.cxd5 Qxd5 13.Rd1 Qe4 14.g3? Nd4 15.Qd3 Nc2+ 16.Kd2 Bf5 17.Qxe4 Bxe4 18.Nxe5 Rad8+ 19.Kc1 Rxd1+?? (A complete oversight. 19...Nd4! wins a whole rook) 20.Kxd1 Bxh1 21.Kxc2 Rc8 22.Nd3 Bd5 (The exchange ahead, I'm struggling to find a plan for this endgame...) 23.Nf4 Bc6 24.e3 Be4+ (Where to put this damn bishop...?) 25.Kc3 Rc8+ 26.Kd4 Bg6 (Puh-leeeze - a bishop!) 27.Bc4 (Awww...) 27...b5?! (Plan B. It shouldn't have worked... I'm usually prepared to give my opponent counterplay if it means I have a clear plan ahead, but maybe here I've given White too much to play for....) 28.Bxb5 Rc2 29.b4 Rxf2 30.h3 Rd2+ 31.Kc3 Rd1 32.a4 Be4 33.a5 g5 34.Ne2 h5 35.Bc4 Bg2 36.h4 gxh4 37.gxh4 Rh1 38.Nf4 Bf3 39.b5 Rxh4 (All part of Black's plan, but White must really have fancied his chances here, and with good reason. It looks as though Black has overcommitted himself on the K-wing. Can he get back in time to stop White Q-side pawns?) 40.b6 axb6 41.axb6 Rh1 42.Bd5! Bxd5 43.Nxd5 Rb1 44.Nb4! Rc1+ (Now, with 45.Nc2!, White could force the draw [45...Rb1 46.Nb4], since the rook can't break out through to his own back rank in time to stop the b-pawn. Was his 45th was a bid for victory or an oversight? I've no idea...) 45.Kd4? Rc8 46.Kd5 h4 47.b7 Re8 48.Kd6 h3 49.Nd3 h2 50.Nf2 Kg7 (At last the Black king bestirs himself to take a hand...) 51.Kc7 Kg6 52.Kd7 Rb8 53.Kc7 Rxb7+ (A rook sac this late in the ending! But this had been planned long since...) 54.Kxb7 Kg5 55.Kc6 Kh4 56.Kd5 Kg3 57.Ne4+ Kf3 58.Kd4 h1=Q 59.Nd2+ Ke2 0-1
Who says endgames can't get exciting? A fighting game I was lucky to win...
Cheers,
Ion
tugger 56 ( +1 | -1 )
Q-sac thanks ccmcacollister, sorry, the puzzle seems to have disappeared, so i've put it up again, probably slightly different, and there is also another Q-sac puzzle for you...

puzzles 975 and 994...

975 was from a game, and was incredibly sweet, and 994 is a puzzle based on a real game, but unfortunately not on gk, so i am guessing the positions of the pieces. the mate is correct.

sorry, i could not find a way to link directly to the puzzles, so here's a link to the puzzle index...

-> gameknot.com
ionadowman 52 ( +1 | -1 )
Interesting link tugger indicates... ...It seems you don't have to be a paying subscriber to submit puzzles or finishes that one is proud of from one's own games neither. One question: is there some requirement to state "Mate in x moves"? I notice some puzzles aren't really plays for mate...
Maybe what's indicated is the old Informator system, which subdivided its 'puzzles' by category (middlegame and endgame; with the sort of thing to be looked for: win of material, forced mate, draw...). But any other indication was given by 1.? or 1....? to indicate whose move it was.
Cheers,
Ion
tugger 48 ( +1 | -1 )
ion... no, you do not need to be a payer to submit, you simply need to have a 1500+ rating. and yes, you would need to select either white/ black to win/draw in 1/2/3/4/5/6/7/8/9/10/10+ moves... so in the case of material gain, you would select white to win in 10+, then state in the description what the goal is...

my only complaint is once a puzzle is submitted, the author cannot delete or edit it, so if, which has happened a few times, you were to discover an error, it's stuck there until a few people have voted it 0.
ionadowman 74 ( +1 | -1 )
Thanks, tugger... I thought as much...
Speaking of puzzles, here's one that could not be placed on the puzzle link, that is supposed to test something about one's 'chess sense' (tho' I've forgotten what...). Imagine a board that has an infinite number of ranks and files, but has one finite corner: the square a1. That is, if you are White, the left hand corner is there where the left hand corner usually is, but the board stretches an infinite number of squares in front of you, and to your right. On a1 [calling it (1,1) might be easier for this puzzle] stands your (White) King; on b1 (2,1) a White Rook. Somewhere 'out there' is a lone Black King, standing on the square (x,y) say. The question is: can White force checkmate on the BK?
(If you answer 'no', can you say why not? If you answer 'yes', can you state how?)
Cheers,
Ion
mattdw 139 ( +1 | -1 )
Infinite chess board.. I think white could checkmate the black king as the white king will always have the advantage of being able to move diagonally and will actually be able to eventually aid the rook and thus force the black king back to the finite corner. To put this into practice what white needs to do is to cut off one of the 'infinite directions' with the rook by moving it to a column or file adjecent to the black king and some arbitrary number of squares away from the black king in the other direction (i.e making a very big rectangle to block the king) and then march the white king diagonally away from the finite corner and only moving the rook many squares away to cut off alternate directions (it is important that the way the rook moves to safety has to include enough of both directions otherwise the white king moving diagonally would be pointless) when the black king gets adjecent, thus effectively halving the speed of the black king relative to the white king (it takes twice as many moves to go up three then right three than it does to just move diagonally three). Repeating this pattern would eventually allow the white king catch up with the rook before the black king and the standard mating pattern would follow.
ccmcacollister 62 ( +1 | -1 )
almost forgot The other Q-sac from that month
board #4256057
Looking at the game on move 41 when the Queen is first attacked by a Rook it occurred to me that it can probably sac there and win with the center pawns. But decided it would be very nice being able to proceed with a Q sac in the bag, using the Queen till then. So it comes a little later.
Had another one in blitz this month, if I can dig it up again.
Interesting game ionadowman
In a dogfight, but like the Red Baron you triumph in the end! :)
bittersweet_ballad 30 ( +1 | -1 )
infinite chess board doesn't seem to be possible!

The white rook would limit the black king's movement by enclosing it in a 'box.' But since the black king would be closer to the white rook than the white king, it would always be able to make the rook move away, and make the box bigger.
bittersweet_ballad 19 ( +1 | -1 )
on second thought, it does seem possible.

mattdw was right; since it is faster to go diagonally, the white king will catch up with the rook.

very interesting puzzle!
yanm 83 ( +1 | -1 )
Infinite chess board... I would say that it is impossible. Below is a sketchy 'proof':
Lets imagine the situation where the black king is enclosed in a box by the white rook, and where the white king is situated on the right and below of the black king. In this case, it is always possible for black to augment the distance between their king and the white king (or at least keep the same distance) by always moving the black king one square in direction to the white rook. Say that white moves their king one square in direction to the black king then the distance is kept the same after black moves. On the other hand, if the black king comes one square near the rook, white needs to move the rook thus increases the box size; and after black move, the distance is increased.
bittersweet_ballad 16 ( +1 | -1 )
yanm but once black's king gets to the edge of the box, he has to move vertically, or to the right, towards the rook. The white king, however, can move diagonally (faster).
ionadowman 129 ( +1 | -1 )
I thought I'd wait... ...rather than respond immediately to mattdw's solution. Fascinating responses, well argued either way.
mattdw got it pretty much. White's first move will be to play the rook to (x+1, 1) [R(2,1)-(x+1,1)]. The BK ain't going to go any further rightwards. Black can do no better than to flee up the x-file. White now moves his rook up the (x+1) file, the optimal square being (x,2y+3) [assuming x < y; (x, 2x+3) if x > y], but moving further won't hurt. Black goes after the rook, whilst the WK runs up the long diagonal. Eventually the BK will hit the WR by moving to (x,2y+2). At this point you hope that the WK has already reached the square (x+2, x+2). Then you move the rook to (2y+1, 2y+3), expanding the box, perforce, but preparing a reception committee for the BK. Natuarally, BK goes after the WR. WK continues along his diagonal, reaching (2y+1, 2y+1), just after the BK reaches (2y-1, 2y+2) - I'm still assuming x<y - such that the BK can no longer approach the rook. Thereafter it's merely a mustering exercise, as mate is forced.
Try substituting numbers, the BK on (3,6), say, or (6,3). A 15x15 board should do...
Black can try to interrupt the process by molesting White's K but he can't stop it from getting 'outside the box' where the BK can not follow, then racing to protect the rook, whereupon Black has no further resource.
White doesn't have to be as rigorous as this. It's clear that given this task, mattdw would have forced the mate, no problem.
Cheers,
Ion
ionadowman 4 ( +1 | -1 )
All of which... ... is a long way from Q sac's etc...
Sorry, Craig.
Ion
tugger 81 ( +1 | -1 )
yanm i was of the same opinion as you, even after reading the explanation, and even went to the bother of typing a long explanation as to how black can continue to keep the distance, but i found the solution just as i was about to post it!
the easiest way to explain it is with every white king move, he goes up one and right one. when black reaches the edge of the box, it can only move either up or right, not both. so white's king is making twice as many moves as black's. once black finally reaches the rook, the rook simply moves right, stopping black going up any further. black must go right. while white's king is still maybe three ranks lower, so long as it more than three files to the right, it can block the black king advancing to the rook. 1-0.