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| Apr-16-09 | | whiteshark: <Once> Should I blame Dvorestsky and Muller for teaching me wrong? :D |
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| Apr-16-09 | | c o r e: Kh7 was my first choice, but I don't see the draw. Back to the bottle! Oops! I meant "drawing board". |
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| Apr-16-09 | | njchess: A drawn position if Black plays Kh7 (Kh6 or Kh5 lead to a win for White). Without going into variations, the idea is that White cannot advance his pawn without incurring perpetual check. Also, in this position, White cannot force Black to exchange his rook, nor can White build a bridge to protect his king (as in a Lucena position). To be fair, Rook vs. Rook and Pawn endings are complex; filled with "rules" that almost always have exceptions. It is difficult even for GMs to analyze correctly. That said, I suspect after 91 moves, fatigue and time trouble might have been factors for GM Tseshkovsky. As an aside, this is one position that most computer programs probably give White a hefty advantage (i.e. +3 to +4 I'm guessing; the equivalent of a minor piece). That is due to the difficulty of interpreting these positions as well as programming the positional concepts. |
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| Apr-16-09 | | Once: Okay, a quickie on Lucena vs Philidor...
In the endgame of K+R vs K+R+1 pawn, the fight comes down to whether the pawn can queen. This means that the queening square becomes all important. It all depends on whose king gets safely to the queening square first. If the attacker gets his king to the queening square in front of his pawn then we normally end up with a winning Lucena position. If the defender gets his king there first, it is often a Philidor draw. In both cases, the defender has two main tactics - endless checks or cover the queening square with more material than the other guy. The attacker needs to prevent these tactics - ie escape the checks and control the queening square for himself. Lucena:
click for larger viewWhite controls the queening square, but he needs to get away from the rook checks. Here is how: 1. Re1+ Kd7 (1... Kf6 2. Kf8 and the pawn cannot be stopped) 2. Re4 (getting ready to shield the king from the rook checks) Rh1 3. Kf7 Rf1+ 4. Kg6 Rg1+ 5. Kh6 Rh1+ 6. Kg5 Rg1+ 7. Rg4 
click for larger viewMission accomplished. Black has no more sensible rook checks and the pawn storms through. Philidor:
click for larger view1... Rb6 Controlling the third rank and preventing white's king from moving forwards. White has to push his pawn. 2. e6 Rb1 Now the rook falls back to the first rank where it can check endlessly. 3. Kf6 Rf1+ 4. Ke5 Re1+
Draw. White cannot make progress. There is nowhere on the board for his king to hide (other than the meaningless h8 square which does nothing to further the pawn's career). And marching his king to the first rank to challenge the rook doesn't help either. 
click for larger viewToday's puzzle is halfway between Lucena and Philidor in that neither side has control of the queening square. Black has already forced the pawn forward to the sixth rank and is now well placed to deliver a rain of checks from behind or the side. |
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| Apr-16-09 | | johnlspouge: < <njchess> wrote: As an aside, this is one position that most computer programs probably give White a hefty advantage (i.e. +3 to +4 I'm guessing; the equivalent of a minor piece). > Toga II 1.3.1 evaluates the positions as
[ply 25/56 time 01:15 value +2.94]
91...Kh7 92.f7 Rc8 93.Rc3 Rb8 94.Rh3+ Kg7 95.Rg3+ Kh7 96.Rb3 Rc8 97.Rb4 Ra8 98.Ra4 Rb8 99.Rf4 Kg7 100.Rg4+ Kh7 101.Kd5 Rd8+ 102.Ke5 Rb8 103.Ke6 Rb6+ 104.Kf5 Rb8 105.Rb4 Rc8 106.Kf6 Rc6+ 107.Ke5 Rc5+ 108.Kd6 Amazing...you're good to the nearest decimal :) |
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| Apr-16-09 | | Marmot PFL: Strange that black would resign at this point (or did he forfeit on time?). At any rate the key positions seem to be those with WK on f8, Pf7. With the rook on g3 white can win with Kg8, but by playing Kh7 black stops this and draws with rook checks- Kh7 f7 Rc8 Ke7 Rc7+ (or Kf6 Rc6+ or Kd7 Ra8) and white king has no escape from the checks that does not lose the pawn. |
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| Apr-16-09 | | johnlspouge: Thursday (Medium):
Sax vs Tseshkovsky, 1975 (91...?) Black to play and draw.
Material: Down a P. The Black Kg6 is in check, narrowing the candidates to K moves. Candidates (91…): Kh7
91…Kh7
Now, White no has no shelter from checks.
Rather than muddle through what is essentially a book analysis, I turn to Euwe and Hooper: “A Guide to Chess Endings”. “When the K is blocking the P, Philidor laid down the drawing method a P on any file: Black’s R stays on the third rank, preventing the advance White’s K. When, and if, the P moves to the sixth, Black’s R moves to the eighth, threatening a series of checks on the files.” Diagram 217 in Euwe and Hooper gives a position relevant to the puzzle, with the annotation “When Philidor’s simple method is not practicable, Black draws against a BP (or centre P) by having his R on the eighth rank.” Black draws if his K reaches f8, the stop square for the P, because of checks. Thus, White’s R must stay on the g-file. Then, however, Black checks on the file until the White K hides at f7 or f8. Then, Black prevents mate by playing Rh8-h7-h8, etc. Attempts to build a bridge with the R are doomed to failure, because of checks or draws after the Rs are exchanged. |
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| Apr-16-09 | | Patriot: 91...Kh7 seems to be the move, keeping the king close to the promotion square. 92.f7 (92.Kf7 Rc7+ seems to go nowhere for white; or 92.Rg7+ Kh8 and a draw by stalemate looms) Here I think 92...Re1+ loses. For example, 93.Kd7 Rf1 94.Ke7 Re1+ 95.Kf8 Rh1 (to stop 96.Rh3+ Kg6 97.Kg8  ) 96.Rg7+! (96.Rg8 right away is refuted by 96...Re1; 96.Rg4 is not "building a bridge" in the Lucena position since the black king is only 2 files away) Kh8 97.Rg8+ Kh7 98.Ke7 . Now rook checks fail since the king will zig-zag down the board until the rook can no longer safely give check. 92...Rc8 93.Ke7 Rc7+ 94.Ke8 Rc8+ 95.Kd7 Ra8 = |
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| Apr-16-09 | | awfulhangover: This is neither Lucena nor Philidor position. This is the "Rook on long side and King on short side" defence strategy. So 91.-Kh7 92.f7 Rc8 93.Rc8 Ke7 94.Rc7+ and so one. |
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| Apr-16-09 | | aragorn69: Good endgame lesson by <Honza>! Kudos also to <Once>, even if less relevant. |
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| Apr-16-09 | | cheeseplayer: black plays:
91.. Kh7
92. Rh3+ Kg6
93. Rg3+ Kh7
white must play another move so doesn't get a draw
possibilities are:
1-
94. Rg7+ Kh8
95. Kf7 Rc7+ with repeating checks black forces the white king to surrunder the defence of the pawn and exchanges the rook with rook and then takes the pawn or 2-
94.Rf3 Re1+
95.Kf7 Rh1 then followed by Rh6 by black even if white decided to re-check the black king once the Rh6 arrives there it's a draw..
that's my analysis.. i'm still beginner but that's what i have.. please reply.. let me see what u have
thanks |
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| Apr-16-09 | | cheeseplayer: sorry i found a solution to the second possibility.. although it looks manageble i still didnt figure out how to make a draw please let me what u think though about how to draw this game.. most probably the tactic is to re check the white king till u get him away from protecting the pawn and the black king is near to the pawn.. |
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| Apr-16-09 | | agb2002: <Patriot: ... 92.Rg7+ Kh8 and a draw by stalemate looms)> I think that now wins 93.Re7, with the plan Kf7-Kf8-f7-Re8 followed by Re7-Ke8 or Rd8-Ke8 or Re4 (threatening mate and the Lucena bridge) depending on the position of the black rook. That's why I preferred 92... Kh6, trying to keep the king close to the white pawn, but perhaps I'm missing something. |
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| Apr-16-09 | | penguin496: Excellent puzzle today for learning rook and pawn vs. rook endgame. |
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| Apr-16-09 | | JG27Pyth: A) I'm going to study the kibitzing for a lesson on this R+P ending B) I'm going to ignore the difficulty ratings regarding these Stalemate positions... it's absurd to call this medium if that means (as it means generally) being able to calculate all meaningful variations to a win accurately... IMO If a GM resigns a five piece ending rather than finding a draw -- it's not "medium." No. It's not. |
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| Apr-16-09 | | kevin86: I read that this game should be drawn.White has no place to hide from the checks and if he intends to use the rook to interpose,the black king just moves to the g-file. This is an exception to Lucena's principle because there is so much space west of the pawn for the rook to annoy with checks. |
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Apr-16-09
 | | Jimfromprovidence: This position is a perfect example where the Nalimov table bases can greatly assist in understanding why 91...Kh7 draws and Kh5 or Kh6 do not. The table bases allow you to “walk” through the position ‘til its conclusion. http://www.k4it.de/index.php?topic=...
Other observations... After 91...Kh7 92 f7, 92…Rc8, below, is the only move that draws. All others lose. 
click for larger viewAfter 91...Kh7 92 f7 Rc8, 93 Rc3, below, is a trap. Only 93… Ra8 or 93…Rb8 draw. All others lose. 
click for larger view |
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| Apr-16-09 | | YouRang: Well, the stalemate theme this week certainly suggests 91...Kh7, after which a subsequent f8=Q would render the black K immobile. But it's the only logical move anyway, since it must be there to prevent Rg8 tactics and to move toward the pawn if the white rook leaves the g-file. After 92.f7, I think it's pretty clear that black must check "horizontally" by moving the rook along the c-file. Checking vertically by moving the rook along the 1st rank eventually runs out of steam when the white king hides at f8 and then plays Rh3+ followed by Kg8. It's a little trickier if white plays 92.Rg7+, and frankly I couldn't see all the ways it could go from there. I presume black should play 92...Kh6 (rather than 91...Kh8) to avoid mating threats arising from f8=Q#, but beyond that, I don't think I can calculate all the lines we might see. However it turns out, it can't be any worse for black than resigning! :-) |
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| Apr-16-09 | | Patriot: <agb2002: <Patriot: ... 92.Rg7+ Kh8 and a draw by stalemate looms)> I think that now wins 93.Re7, with the plan Kf7-Kf8-f7-Re8 followed by Re7-Ke8 or Rd8-Ke8 or Re4 (threatening mate and the Lucena bridge) depending on the position of the black rook. That's why I preferred 92... Kh6, trying to keep the king close to the white pawn, but perhaps I'm missing something.> I think you're right. But I don't think there is a Lucena bridge to be made, because one of the keys to Lucena is that the defender's king is cut off three files away from the pawn. |
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| Apr-16-09 | | Eisenheim: Is the stalemate theme this week a product of it being April 15 - tax day? You can never win with taxes, no matter how far you think you are ahead. |
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| Apr-16-09 | | johnlspouge: < <awfulhangover> wrote: This is neither Lucena nor Philidor position. This is the "Rook on long side and King on short side" defence strategy. > Agreed.
< <Jimfromprovidence> wrote: This position is a perfect example where the Nalimov table bases can greatly assist in understanding why 91...Kh7 draws and Kh5 or Kh6 do not. The table bases allow you to “walk” through the position ‘til its conclusion. > Indeed, the exercise was most instructive.
Thanks to both of you. |
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| Apr-16-09 | | WhiteRook48: but the puzzle said 91....? not 91 ? |
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| Apr-16-09 | | ChessEscudero: WHITE wins by 91)...Kh5 92)f7...Ra1 93)f8=Q...Ra6+ 94)Ke5...Ra5+ 95)Kd4...Kh4 96)Qf4+...Kh5 97)Kh6Qg4+...Qg6# With accurate play, Black draws by 91)...Kh7 |
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| Apr-16-09 | | RandomVisitor: 90.f7! Re1+ 91.Kf6 Rf1+ 92.Ke7 Re1+ 93.Kf8 Rf1 94.Re3 Kg6 95.Re7 Rg1 96.Ke8 Rb1 97.Re6+ Kg5 98.f8Q Rb8+ 99.Kf7 Rxf8+ 100.Kxf8 wins. |
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| Apr-16-09 | | Pawnage: Yes, I got it right! Resign! |
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