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|Mar-31-11|| ||NM JRousselle: This looked pretty easy for a Thursday.|
|Mar-31-11|| ||adamico: I honestly have no idea what the difficulty level of a puzzle like this should be because if you know the idea of "building a bridge" you probably saw this in two seconds. I suppose there is some brief calculating to do to make sure that white can queen first, but the real heavy lifting is knowing (or figuring out if you don't know this type of pattern) to shield the king from the rook with your own rook. But I would like to applaud chessgames for mixing in a different kind of puzzle like this with the tactical calculation puzzles we usually get.|
|Mar-31-11|| ||mig55: Indeed very easy. Even I saw it immediately:-)|
|Mar-31-11|| ||dzechiel: White to move (73?). Material even. "Medium."
Looked at this for a while. White's big advantage is his forward c-pawn. But if black can trade his rook for the white pawn, the black king can then escort his own pawn down the board and the white king will be out of play.
So what move prevents black from trading the rook for the pawn? Only one I can find...
I also checked at this point, as it looks to me that black has nothing to play for here, and I expected (correctly) that he resigned.
|Mar-31-11|| ||lost in space: That was very easy.
Blacks threat is 73. c8=Q Rc3+ 74. Kd7 Rxc8 75. Kxd8. Afterwards blacks king is helping his pawn down to g1 with a draw after White exchanged his rook vs the pawn or the resulting queen.
So: 73. Rh5 Rg1 74. c8=Q 75. Rc1+ Rc4 and it is all over. White's rook maneuver is called "stairway"
|Mar-31-11|| ||SpoiltVictorianChild: Anyone familiar with the Lucena position will get this right away.|
|Mar-31-11|| ||alachabre: I have to admit, endgames are my greatest weakness (although I have many). A quick calculation shows the immediate queening of the White pawn leads to a draw:|
73. c8=Q Rc3+
74. Kd7 Rxc8
75. Kxc8 Kf5 and, unless I am extremely weak in my endgame theory, Black can escort the pawn up the board and force White to give up the rook for the pawn, thus a draw by rule.
So, not knowing really if this is related to the Lucena position, which I try to memorize but really haven't yet, I want to play
73. Rh5 so that I can block the check on the c file with the rook and keep my queen. Then there should be time to chase down the Black pawn if necessary, and even if I screw that up, I should still have a QvR ending, which I just might be able to win by move 125. Maybe it's easier than all that after Rh5, but it's late, laundry needs folding and my guitar needs playing.
|Mar-31-11|| ||rilkefan: Dang, I don't get to be happy for seeing this quickly.|
|Mar-31-11|| ||TheBish: Onischuk vs C Balogh, 2008|
White to play (73.?) "Medium"
Looks like we're taking a break from games with queen sacs, to be presented with a very easy (I think) or let's say "easy" R+P endgame on Thursday, that maybe could be given on Tuesday? In any case...
73. Rh5! allows White to queen the pawn, by preparing a shield to Black's intended rook check (73...Rc3+ 74. Rc5). If instead 73. c8=Q? Rc3+ 74. Kd7 RXc8 75. Kxc8 Kf5 and White's king is too far away to assist the rook in preventing Black from queening, so a draw would be the result -- either by Black queening and the rook trading for it, or from the rook giving perpetual check (as Black would not want to blockade the pawn with his king.
|Mar-31-11|| ||Eduardo Leon: 73.h5 was fairly obvious.|
|Mar-31-11|| ||al wazir: Usually when it comes to endgames, I am as the beasts that perish. I lose practically every endgame I play. I saw 73. Rh5 right away and wondered what complications I was overlooking. There were none.|
I think <CG>'s calendar is messed up.
|Mar-31-11|| ||HeMateMe: White creates a Lucerne position.|
|Mar-31-11|| ||Lennonfan: I cant see all the way to mate but this is the easiest thursdays iv ever seen..Rh5 then black cant stop white queening as he only has one check which is blocked by whites rook...white queens first,then its easy....strangely easy!|
|Mar-31-11|| ||M.Hassan: "Medium" White to play
73.Rh5 stops counter play by Black
75.c8=Q> White wins
76.c8=Q> Also White wins
|Mar-31-11|| ||M.Hassan: <al wazir>: Same with me. I am a bad end gamer as well|
|Mar-31-11|| ||newzild: So simple, and yet so instructive - the old "building a bridge" technique.|
|Mar-31-11|| ||gmalino: Today, white SIMPLY needs to get his King out of the c-row and within one move the c-pawn queens.
After looking for Kd/d7 for a while I now wonder why not simply play|
If black takes on c8, King takes back and loses the race to g1, where the black rook has to throw himself away for the g-pawn.
That's why, ok.
Now getting back to this Kb/d7-idea:
Blacks rook will give checks till we play Kc8, which gives black the time to bring his King in, so I don't believe this can be good.
But, NO, there is the opportunity to hide behind blacks King on f8!
That could give white the extra-move he needs.
And now 74....Rc3 doesn't work anymore because of Kd8 and Rd7, deflecting the check.
The imediate Ke6 loses the the imediate c8=Q, I can't see how black can hold this...
|Mar-31-11|| ||Once: Well, yes, building a bridge. Rook and pawn endgames 101. Not much to say that hasn't already been said. If you know the technique then it doesn't really need much thought.|
Fritz says that 73. Kb5 and 73. Kd5 also win. The white king advances towards the rook until it can't check any more. Then white plays Rc6 to safeguard the passed pawn. Evade a few more checks, the queen the pawn and win. Something like this:
73. Kd5 Rd3+ 74. Kc4 Rd1 75. Rh6+ Kf7 76. Rc6 Rc1+ 77. Kd5 Rd1+ 78. Ke4 Re1+
79. Kf5 Rd1 80. c8=Q
But 73. Rh5 is the quickest and cleanest by far.
Incidentally, there is a strategic point here. As the middle game tends to the endgame, good players will often push pawns. This grabs space and starts the race to queening. Then exchange off all the pieces and head for a finish like today's "puzzle".
|Mar-31-11|| ||gmalino: Ok, nice to be the only one who completely missed it.
This brings me to learning new terms like "lucerna-position".|
I also oversaw (in my faulty line) that black always can take the c-pawn and start running for g1....
|Mar-31-11|| ||gmalino: <if only> I wouldn't be so lazy I would have gone to see the game. Took place about two kilometers away from my place.....|
|Mar-31-11|| ||gofer: Black is hoping to play Rc3+ and scoop up the pawn. But he isn't looking to save his rook, as he does it he is simply going to sacrifice it! Leaving white with a very difficult win as the king will come to support Pg4 and then help it to promotion. The only way white can avoid losing is to draw!|
So white has to try to block the king from reaching Pg4 AND some how being being able to bring the rook across to c5...
<73 Rh5 ...>
Black will resign as Pc7 cannot be stopped!
73 ... Rc3+ 74 Rc5 Rxc5 75 Kxc5 g3 76 c8=Q g2 77 Qg8/Qg4 winning
73 ... Ke7 74 c8=Q Rc3+ 75 Rc5 Rxc5 74 Kxc5 g3 75 Qg4 winning
Another interesting position would be as follows
click for larger view
What is the answer then...
|Mar-31-11|| ||morfishine: 73.Rh5 and black is lost.
Maybe CG transposed Tuesday with Thursday?
|Mar-31-11|| ||agb2002: The material is even.
Black threatens 73... Rc3+ followed by ...g3.
Just build Lucena's bridge with 73.Rh5:
A) 73... Rc3+ 74.Rc5 Rxc5+ 75.Kxc5 g3 76.c8=Q Kg5 (76... g2 77.Qg4 + -) 77.Qh3 Kf4 78.Qg2 + -.
B) 73... Rh3 74.Rxh3 gxh3 75.c8=Q h2 76.Qh3 + -.
C) 73... Kg6 74.Rc5 + -.
|Mar-31-11|| ||amaurobius: I missed it. And to make it worse, I do actually know the Lucena position, where you start with the king on the eighth rank and build your bridge gradually. This position is much easier - the bridge is established in two moves!|
So - thank you CG. Too easy for everybody else but instructive for me.
|Mar-31-11|| ||paavoh: A well-conducted middle game by Onischuk. Keeping the advantage, switching targets, trading down, and holding on to the c pawn. A nice model game!|
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