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| Apr-11-10 | | patzer2: For today's Sunday puzzle, 45. f4! entraps the Black King in the middle of the board for a mating attack. The finishing followup 47. Rc7! removes the guard and leaves Black with no answer to the dual threat 48. Rxc3# or 47...d5 48. Rxc3+ dxc3 49. Rd3#. |
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| Apr-11-10 | | znsprdx: <UnsoundHero:> right you are 44.b4 is the setup ...d5 (to free the almost trapped rook) doesn't help 45.Rxd5 with unstoppable f3 mate. Let's face it OTB finding f4 is less than obvious as <wordfunph:> + <YoungEd:.> stated....not withstanding all the boastful claims posted here. What makes this a gem is that the 45...Rh7 line fails to Rxe7+ Amazing Serendipitous Synergy!<Socrates> cute Rh1 as well-ouch...when it is lost it is lost:) |
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| Apr-11-10 | | randomsac: This was really straightforward for Sunday. I saw f4 trapping the king. After that white can do all sorts of stuff to eventually play Rd4#. |
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Apr-11-10
 | | ray keene: there was no endgame prize sadly in this event-i particularly liked the dual rook sac with either Rxe7+ or Rc7 to administer the coup de grace. thanks for all the comments. |
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| Apr-11-10 | | sethoflagos: The first thing that jumps out of this position is the immobility of the black position. The threat of Rxe7# places an absolute burden on Rg7, and consequently both pins Pe7 and renders Pg3 safe. So 45. f4 is possible, blocking Pg5, stalemating the BK and opening up the possibility additional mating threats(e.g. 45. ... b3 46. Rd1 threatening Rd4#) 45. ... d6 46. Rxd6 would mate next move from e5 or d4. Black is almost in zugzwang with 45. ... Rc6 pretty well a forced move good or ill. <45. f4 Rc6>
Now the key move threatening 47. Rd4# is
<46. Rd1! ....> if 46. ... Rxc4 47. Rc7! is forced mate. <46. .... e5> forced, dropping a rook. |
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| Apr-11-10 | | znsprdx: <socrates>I may have found a spoiler to your 46.Rh1 alternative: ( with a humble begging your pardon <ray keene>) ...Rxa5!? giving up the rook
The kind of resourceful move my neighbor often finds in dead lost positions :) 47.Rx[R]h7 Ra2+
48.Kf1 Kf3!
49.Ke1 Kxe3
50.Kd1 Kd3and white cannot even return the rook 51.Kc1 Kc3 and now we have a problem within a problem
< 
click for larger view> Black's mate threat combined with a potential b3 push just may be a draw!... 52.Kb1 Rb2+ 53.Kc1 Rc2+
54.Kd1 Rd2+ 55.Ke1 Kc2
56.Rb7 Rd1+ 57.Ke3 Rd2+
58.Ke3 Rd3+ 59.Ke2Rd2+
60.Ke1 Rd1+ 61.Kf2 b2
and even 62.Rh2 may not work after Kc1! |
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| Apr-11-10 | | Eduardo Leon: Today's puzzle was beautiful but solvable. What was truly insane was to find out this possibility before playing <43.♖d7> and <44.b4!>. Perhaps <43.♖d7> makes some sense without the mating idea, because it ties both black rooks to the defense of the e7 and a7 pawns. But <44.b4!> was clearly targeted at creating a mating net. It had two purposes: First, getting rid of the only pawn that protects d4. Second, creating a path where the rook in the seventh rank could sacrifice itself for black's queenside rook, should black defend himself with ♖c6 and ♖xc4. If <44...♔e5>, then <45.b5>, trapping the rook. 
click for larger viewIf <44...♖h7>, then again <45.b5>. 
click for larger viewIt's tempting to play <45.♖d1?>, with the idea <45...axb4?? 46.♖xe7+!! ♖xe7 47.f4>. 
click for larger viewBut, black gets his king outside the mating net first: <45...♔e5!>, and the b4-a5 pawn chain is hanging. 
click for larger viewThe computer-like answer would have been <44...♖c6>, since it doesn't lose anything but a pawn: <45.b5 ♖c8 46.♖xa7>. 
click for larger viewHowever, white was previously a pawn up, so he is two pawns up now (duh!), and those two pawns are passed, connected and well-protected. I don't doubt the computer evaluation of this position exceeds +2.0. All of this wouldn't have been possible without <43.♖d7> and especially <44.b4!>. In conclusion, <44.b4!> was <the> move. |
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Apr-11-10
 | | tarek1: I suggest
<45.f4>
removing the last square (e5) accessible for the black king to run back home
and completing the mate net. The threat is Rd1 and Rd4#.
Strangely the full tempo black has to counter this threat is not enough.
The king cannot run away, the square cannot be defended by e5 because of the rook hanging on g7,
taking on g3 only results in Black getting mated by Rxe7... The variations :
A) <45...Rxg3 46.Rxe7#> B) <45...e5 46.Rxg7> C) <45...Rh7> trying to a check on h2 but <46.Rh1!> and
B1) if <46...Rxh1> then <47.Rxe7#>
B2) if <46...Rg7> back <47.Rd1!> and Rd4# is again unvoidable. D) <45...Rc6 46.Rd1 Rxc4> defending d4 but... <47.Rc7!>
The rook is taboo <47...Rxc7 48.Rd4#> and <47...d5> doesn't solve the problem : <48.Rxc4 dxc4 49.Rd4#> So I don't see a defense that doesn't result in mate or loss of a rook. Let's check how it went... |
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| Apr-11-10 | | kramputz: < znsprdx> Two White Kings ?? Looks like a patricide. Which is Brutus? |
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Apr-11-10
| | tarek1: <znsprdx>
Clever try, I don't know if it works. I too suggested Rh1 because I missed Rxe7.
One of your variations caught my eye, in that it seems to me there is another way to play for white than the one you show :From the diagram position (with the king on c3 being black of course)
<1.Kb1 Rb2+> and now I diverge with <2.Ka1> instead of your Kc1.
So if <2...a5 3.Ra7>
and if <2...Rg2> simply <3.Rh1> I seems to me that white can bring back his rooks to the defense and the rook up white has will tell. |
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Apr-11-10
 | | Jimfromprovidence: <Random Visitor> <44.f4! also works.>
click for larger view No need for 44 b4 first, although it's a beautiful concept and wins easily. After 44 f4, if 44…d5, then 45 Rxd5 Re6 46 Rad1 Rxg3 47 R1d4+ cxd4 48 Rxd4#.
click for larger view
If 44 Rh7, then 45 Rh1!
click for larger view
If 45…Rxh1, then 46 Rxe7#. If 45..Rg7, then 46 Rh6, etc. |
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| Apr-11-10 | | Eduardo Leon: <Phase 1> Securing the advantage Black's opening play was aimed at winning the d4 pawn (7...♘e4). However, the soundness of this idea was calmly contested with some accurate minor piece play (10.♘h4). After the exchanges, white recovered his pawn and had a clear bishop vs knight in an open position advantage (14.♗xb7). <Phase 2> Evolution and transformation of the advantage Black lost a tempo playing a move he would later regret (15...♖b4). White grabbed the chance to create weaknesses in black's pawn structure (17.h5) and exploit them (18.♕g5, 21.♕e4). When it seemed like black was consolidating (21...♘f5), white exchanged his bishop vs knight advantage for an advantage in the pawn structure (23.♗xf5) and won a precious tempo tying the black queen to the defense of her pawns (24.♕e6). <Phase 3> Heavy piece play Black's inability to play 24...♕h3 meant white could play 25.♔g2, which in turn meant the black king was under attack in the h file! Black decided to give up a pawn (25...♕f7) he could have retained (25...♕g6), but that pawn would have actually been a hindrance. Black still couldn't consolidate. The weakness of the a7 and e7 pawns meant that he could not contest white's assertion of his domination of the h file (29.♖h4, 30.♖hh1), despite his intention to do so (28...♖bb8). The only thing black got for his pawn was some air for his king (29...f5), in the eventuality that white launched an all-out attack with his pieces. Of course, at the cost of a tempo. White could have launched that attack anyways (31.♕d5, 32.♕d2, threatening 33.♖g5 and 33.♖h6), winning immediately. But, overlooking that possibility, he chose to enter an endgame (31.♕h5 ♕xh5 32.♖xh5) in which he still had the upper hand, but had to work harder to exploit it. <Phase 4> Endgame technique Despite the absence of queens, there was a threat (33.♖h7+ ♔g6 34.♖1h6+ ♔g5 35.f4+ ♔g4 36.♖h4#) black had to counter, which he did (32...♔f7). Again, at the cost of a tempo, which white used to further corner the lonely b8 rook (33.♖h8 ♖b6 34.♖a8 ♖a6 35.a4). Then came some desperate tries by black (35...♖e6, 36...♖b6), which could be easily neutralized (36.e3, 37.♖b1). White finally asserted his positional domination (38.a5 ♖a6 39.♖a1), but still faced the question of what he could do with it. Black's final inaccuracy (43...♔e4) answered that question. |
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| Apr-11-10 | | DarthStapler: I got the first move and the general idea |
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Apr-11-10
 | | chrisowen: Mortensens easily dead? 45f4 carp my fish around think Keene. Ill publish my thoughts. Prior to Ke4 theres hope, and anchors it he should think of Ke6. F4 hes under, the iron see is band rook 46Rd1 47Rd4 mate threat, actualty is sterling no? Instrument of his plays Rc7 cohere I. |
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| Apr-11-10 | | tharsitis: I don't understand,why didn't black play 43...Ke6,to move his king away from white pawns and to threat the rook?What would be wrong with that? |
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Apr-11-10
 | | Sneaky: Had Keene played 44.f4 (a move earlier) would the combination still be valid? I don't understand 44.b4 and what it does to help the combination work. |
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| Apr-11-10 | | Shams: <Sneaky> doesn't white need to pull the c-pawn off control of d4, to set up the final mate? |
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| Apr-11-10 | | Eduardo Leon: <tharsitis>, indeed, 43...♔e4 was the decisive mistake, although black was already much worse. |
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| Apr-11-10 | | RandomVisitor: After 44.f4 black quickly falls apart:
click for larger view Rybka 3: <16-ply>
+7.23 44...Rxa5 45.Rxa5
+7.26 44...Rh7 45.Rh1
+9.75 44...Rf7 45.b4
+12.71 44...Rc6 45.Rh1
+18.17 44...e5 45.Rxg7 |
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| Apr-11-10 | | wals: Rybka 3 1-cpu: 3071mb hash: depth 27:
White was in control from move 18 and
victory was guaranteed on move 43.
+1.10 18...f6 best was Qd7 +0.44
+2.18 21...Nf5 best was Re8 +1.57
+1.41 23.Bxf5 best was Kg2 +2.28
+2.79 24...Rb7 best was Rbb8 +1.38
+3.18 30...Rf6 best was Rbe8 +2.69
+1.50 31.Qh5 best was Qd5 +3.18
+6.15 43...Ke4 best was Rh7 +1.04 |
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| Apr-11-10 | | gofer: This one took a while, but once you see the two themes it is obvious; 1) Create a mating net, by trapping the king.
2) Overwork Ra6 to the point where it has no choice but to fail. 45 f4!
Now the king is trapped and Rg7 is tied to the 7th rank to stop Rxe7#, what is worse is
that white is going to play Rd1 and then Rd4#, so black's options are severely limited. Option 1 (lose quickly)
45 ... Rc6
46 Rd1 Rxc4
47 Rc7! Rc2+ (e5 48 Rxc4# or Rxc7 48 Rd4#)
48 Rxc2 e5
49 Rc4#
Option 2 (lose slowly)
45 ... e5
46 Rxg7 Rc6
47 Rc1 a6
48 Re7 Rc5
49 Re6 Rc6
50 c5 Kd5
51 Rxd6+ Rxd6
52 cxd6 Kxd6
53 fxe5 Kxe5
54 Rb1 winning
Time to check... |
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| Apr-14-10 | | njchess: Black plays the opening safely with a draw in mind and by 15. Bf3, GM Keene has achieved a slight advantage with an active bishop versus Black's less active knight. Black plays 15. .... Rb4 to limit White's queens movement, but at the cost of immobilizing his rook, and thus, given the pawn structure, leaving them uncoordinated throughout the rest of the game. With the position now locked, GM Keene starts the king side assault. Curiously, over the ensuing moves, Black makes no meaningful attempt attempt to activate his poorly placed knight and try to generate some counterplay. Not surprisingly, 12 moves later, Black drops a pawn and his king is now exposed. By move 32, we are now in a rook endgame with Black desperately seeking a draw. 34. ... Ra6? is a painful move for Black. Without going through the variations, Rb7 would seem to be a better alternative. Since Black's rooks lack any coordination, Black has little if any counterplay. White's advantage at this point is a winning one and the outcome predictable. Still, 43. ... Ke4?? seems innocent enough until 45. f4!. Together with the inevitable opening of the queenside, Black finds himself the victim of a diabolical trap. A shame there was no endgame brilliancy prize, for you certainly deserved it GM Keene. Nicely played. |
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| Jul-29-18 | | nummerzwei: <Sneaky: Had Keene played 44.f4 (a move earlier) would the combination still be valid? I don't understand 44.b4 and what it does to help the combination work.> Indeed! 44.b4 looks reasonable to free up the d4-square, but concrete calculation schows that this is not necessary. When I did the exercise, I rejected 44.b4 because of the text defence (overlooking 47.Rc7!!), and because I had satisfied myself that 44.f4 wins. I suppose Keene worked it out to the end at move 43 and didn't notice that 44.b4 is actually superfluous. |
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Jul-29-18
 | | beatgiant: <Sneaky>,<nummerzwei>
What does White play after 44. f4 <Rh7>? (In the game line, after 45...Rh7 White has <46. Rxe7+> Rxe7 47. Rd1 followed by 48. Rd4#) |
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| Jul-29-18 | | nummerzwei: <beatgiant>
Here one needs to see 44...Rh7 45.Rh1! Rg7/Rf7 46.Rh6 threatening 47.Re6#. |
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