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Up Topic The Rybka Lounge / Test Positions / 2 problems in Hard-Talkchess-2020
- - By dorszcz (**) Date 2021-01-11 13:28 Edited 2021-01-11 13:30
Recently I have been searching for best tactical engines for solving hard positions. I have almost finished and soon I am going to share the results.
I ran one of the engines in Hard-Talkchess-2020 using very similar conditions to Vincent's conditions and I analyzed all the positions that were not solved by an engine.

It seems that from 17 unsolved positions there are 2 positions where there are missing solutions. These positions are:

1q1r3k/3P1pp1/ppBR1n1p/4Q2P/P4P2/8/5PK1/8 w - - bm Rxf6; id "Hard-Talkchess-2020.010"

Here Rxf6 wins the fastest but Qe7 is leading to a simple win too.
The eval for this line was +7.97.
1. Qe7 Qc7 2. Kg1 Kg8 3. Rd3 Qb8 4. Re3 Rf8 5. Qe8 Nxe8 6. dxe8=Q Rxe8 7. Rxe8+ Qxe8 8. Bxe8 Kf8 9. Bc6 Ke7
It is a kind of a position where almost everything can win for example Kg1 or Kf3.

1rb2r1k/3p1pp1/p3p2p/1p2P3/4q3/1N2B1R1/PPP1N1P1/2KR1B2 w - - bm Nf4; id "Hard-Talkchess-2020.026"

Besides Nf4 there is Nc5. It leads to the variant below with high eval +2.99.
1. Nc5 Qf5 2. Nf4 Qxe5 3. Bd3 Kg8 4. Rh1 f5 5. Be2 Kh7 6. Ncd3 Qc7 7. Bd4 Rf7 8. Nh5 Bb7 9. Be5 d6 10. Nxg7 Rxg7 11. Rxg7+ Qxg7 12. Bxg7 Kxg7
Parent - - By Akbarfan (***) Date 2021-01-16 21:49 Edited 2021-01-17 04:02
But 1.Rxf6 is much much better, it leads to mate soon.

10: Hard-Talkchess-2020.010 Line, Hard-CCC_2020 final
1q1r3k/3P1pp1/ppBR1n1p/4Q2P/P4P2/8/5PK1/8 w - - 0 1


Analysis by Crystal 110920 Cry3.0:

1. +- (151.48): 1.Rxf6 gxf6 2.Qxf6+ Kg8 3.Qxh6 Rxd7 4.Bxd7 Qa8+ 5.Bc6 Qc8 6.Qg5+ Kh8 7.Bd5 Qg8 8.Kf3 b5 9.axb5 axb5 10.h6 Qg6
2. +- (12.34): 1.Kg1 Kg8 2.Qe7 Qc7 3.Kg2 b5 4.axb5 axb5 5.Bxb5 Qb7+ 6.Bc6 Qc7 7.Kg1 Qa5 8.Ba4 Qc7 9.Bb5 Qc1+ 10.Kg2 Qc7 11.Bc6
3. +- (11.27): 1.Qe7 Ng8 2.Qe5 b5 3.axb5 axb5 4.Bxb5 Qa8+ 5.Kg1 Nf6 6.Qe7 Qb8 7.Rxf6 gxf6 8.Qxf6+ Kg8 9.Bc6 Qb6 10.Qxh6 Qb1+ 
4. +- (8.74): 1.Kf1 b5 2.a5 Kh7 3.Qe7 Ng8 4.Qe4+ Kh8 5.Qe5 Nf6 6.Rd3 Qxe5 7.fxe5 Nxh5 8.Rd4 Kh7 9.Bb7 Nf4 10.Rxf4 Rxd7 11.Bxa6

Now it shows mate in 31!

Analysis by Crystal 110920 Cry3.0:

1. +- (#31): 1.Rxf6 gxf6 2.Qxf6+ Kg8 3.Qxh6 Rxd7 4.Bxd7 Qd8 5.Qg5+ Qxg5+ 6.fxg5 f6 7.Be6+ Kg7 8.h6+ Kg6 9.a5 bxa5 10.Bf5+ Kxf5 11.h7 fxg5 12.h8Q a4 13.Qa1 Ke6 14.Qxa4 Ke7 15.Qa5 Kf6 16.Qxa6+ Ke5 17.Qb5+ Kd6 18.Qxg5 Kc6 19.Qa5 Kb7 20.Qb5+ Kc7 21.Kf3 Kd6 22.Kg3 Ke7 23.Qd5 Kf6 24.Qd6+ Kf7 25.Qd7+ Kf6 26.Kf4 Kg6 27.Qe8+ Kf6 28.Kg4 Kg7 29.Kg5 Kh7 30.Kf6 Kh6 31.Qg6#
2. +- (13.32): 1.Qe7 Qc7 2.Qe5 b5 3.axb5 axb5 4.Bxb5 Rg8 5.Bd3 Rd8 6.Bf5 Kg8 7.Qe7 Qa5 8.Kg1 Qa1+ 9.Kh2 Qa5 10.Rd5 Qa8 11.Rc5 Nxd7

Finally mate in 22 !!
Parent - By user923005 (****) Date 2021-01-17 06:06 Upvotes 1
If the other moves clearly win also, is an engine wrong if it chooses them?
Admittedly, the key move is the prettiest.
Parent - By dorszcz (**) Date 2021-01-17 14:10
Rxf6 is better, but not much much better.
Parent - By MrKris (****) Date 2021-01-19 17:23

> But 1.Rxf6 is much much better, it leads to mate soon.


(Ryzen 7 2700X 14 threads, 11 day old Stockfish_21010817, abrok avx2) :

After 1.Rxf6!!:  (Arena restarted first)
Stockfish, PV=4, took only 117 seconds to find Mate in 22.
[FEN "1q1r3k/3P1pp1/ppB2R1p/4Q2P/P4P2/8/5PK1/8 b - - 0 1"]

1. ... gxf6 2.Qxf6+ Kg8 3.Qxh6 Rxd7 4.Qg5+ Kf8 5.h6 Qc7 6.Bxd7 Qb7+ 7.Kh2 Qxd7 8.Qg7+ Ke7 9.Qe5+ Kd8 10.h7 Qe8 11.Qxe8+ Kxe8 12.h8Q+ Ke7 13.f5 b5 14.Qe5+ Kd7 15.f6 Kc6 16.Qe8+ Kb7 17.Qxf7+ Kc6 18.Qe7 Kd5 19.f7 Kc4 20.Qe3 Kb4 21.f8Q+ Ka5 22.Qc3+ Kb6 23.Qb8+ {mate}

But before 1.:   (Arena restarted first)
Stockfish, PV=4,  took almost 2 hours,110 minutes to find that 1.Rxf6!! is best, still no mate, just +14.23 evaluation.

At 88 minutes, just before finding 1.Rxf6!! at 110 minutes, best (of PV=4) is:
[FEN "1q1r3k/3P1pp1/ppBR1n1p/4Q2P/P4P2/8/5PK1/8 w - - 0 1"]

1.Kf3 Kg8 2.Qe7 Qc7 3.Kg2 Kh8 4.Kg1 Ng8 5.Qe5 Nf6 6.Re6 Rxd7 7.Re8+ Ng8 8.Rxg8+ Kxg8 9.Qe8+ Kh7 10.Qxd7 Qxf4 11.Kg2 b5 12.a5 b4 13.Bf3 g6 14.hxg6+ Kxg6 15.Qd3+ Kg7 16.Be2 Kh8 17.Qd5 Qf6 18.Qc5 Qd8 19.Qxb4 Qg5+ 20.Bg4 Qd5+ 21.Bf3 Qg5+ 22.Kf1 Qc1+ 23.Qe1 Qb2 24.Qe8+ Kg7 25.Kg2 Qf6 26.Qd7 Kf8 27.Qc8+ Kg7 28.Qg4+ Kf8 29.Qh5 Qg7+ 30.Kh3 Qf6 31.Kh2 Ke8 32.Kg2 Qe6 33.Qg4 Qf6 34.Qc8+ Ke7 35.Qc5+ Kd8 36.Qd5+ Ke8 37.Qc6+ Qxc6 38.Bxc6+ Kd8 39.Bb7 Kc7 40.Bxa6 {white K, B, 2 pawns; black K, 2 pawns} ____________________
R7 2700X 14th , 8 GBh , Sy.6 
PV=4 , best at bottom
(+/- good/bad for mover)

FEN: 1q1r3k/3P1pp1/ppB2R1p/4Q2P/P4P2/8/5PK1/8 b - - 0 1 

Stockfish_21010817:  ---------------------------------------------------------------------------
 67/19  01:57    3,257,950k  27,966k  -M9  1. ... b5 2.Rxf7 Qxe5 3.fxe5 Kg8 4.e6 Rb8 5.Bd5 bxa4 6.e7 Rb4 7.e8Q+ Kh7 8.Rxg7+ Kxg7 9.Qe7+ Kh8 10.d8Q+
 67/23  01:57    3,257,950k  27,966k  -M11  1. ... Kg8 2.Rd6 Rf8 3.Bd5 Kh7 4.Qf5+ Kh8 5.Be4 g6 6.Qe5+ f6 7.Rxf6 Rg8 8.Rd6+ Rg7 9.d8R+ Qxd8 10.Rxd8+ Kh7 11.Qe8 a5 12.Qh8+
 67/39  01:57    3,257,950k  27,966k  -M19  1. ... Qxe5 2.fxe5 gxf6 3.exf6 Kh7 4.Kf3 Rb8 5.Ke4 b5 6.Ke5 b4 7.Kd6 b3 8.Kc7 Rg8 9.Be4+ Kh8 10.d8Q Rxd8 11.Kxd8 b2 12.Ke7 Kg8 13.f4 a5 14.f5 Kh7 15.Kxf7 Kh8 16.Ke7 b1Q 17.Bxb1 Kh7 18.f7 Kh8 19.f8Q+ Kh7 20.f6+
 67/47  01:57    3,257,950k  27,966k  -M23  1. ... gxf6 2.Qxf6+ Kg8 3.Qxh6 Rxd7 4.Qg5+ Kf8 5.h6 Qc7 6.Bxd7 Qb7+ 7.Kg1 Qxd7 8.h7 Qd1+ 9.Kg2 Qd4 10.Qg8+ Ke7 11.h8Q Qxh8 12.Qxh8 b5 13.axb5 axb5 14.Qe5+ Kd7 15.Qf6 b4 16.Qxf7+ Kd6 17.f5 b3 18.Qe6+ Kc7 19.Qxb3 Kd7 20.f6 Kd6 21.f7 Ke7 22.Qd5 Kf8 23.Qf5 Kg7 24.f8Q+
---------------------------------------------------------------------------
 68/19  01:57    3,269,991k  27,974k  -M9  1. ... b5 2.Rxf7 Qxe5 3.fxe5 Kg8 4.e6 Rb8 5.Bd5 bxa4 6.e7 Rb4 7.e8Q+ Kh7 8.Rxg7+ Kxg7 9.Qe7+ Kh8 10.d8Q+
 68/23  01:57    3,269,991k  27,974k  -M11  1. ... Kg8 2.Rd6 Rf8 3.Bd5 Kh7 4.Qf5+ Kh8 5.Be4 g6 6.Qe5+ f6 7.Rxf6 Rg8 8.Rd6+ Rg7 9.d8R+ Qxd8 10.Rxd8+ Kh7 11.Qe8 a5 12.Qh8+
 68/39  01:57    3,269,991k  27,974k  -M19  1. ... Qxe5 2.fxe5 gxf6 3.exf6 Kh7 4.Kf3 Rb8 5.Ke4 b5 6.Ke5 b4 7.Kd6 b3 8.Kc7 Rg8 9.Be4+ Kh8 10.d8Q Rxd8 11.Kxd8 b2 12.Ke7 Kg8 13.f4 a5 14.f5 Kh7 15.Kxf7 Kh8 16.Ke7 b1Q 17.Bxb1 Kh7 18.f7 Kh8 19.f8Q+ Kh7 20.f6+
 68/45  01:57    3,269,991k  27,974k  -M22  1. ... gxf6 2.Qxf6+ Kg8 3.Qxh6 Rxd7 4.Qg5+ Kf8 5.h6 Qc7 6.Bxd7 Qb7+ 7.Kg1 Qxd7 8.h7 Qd1+ 9.Kg2 Qd4 10.Qg8+ Ke7 11.h8Q Qxh8 12.Qxh8 b5 13.a5 b4 14.Qa8 Kf6 15.Qxa6+ Kg7 16.Qe2 b3 17.a6 b2 18.Qxb2+ f6 19.a7 Kf7 20.a8Q Kg6 21.Qd8 Kh6 22.Qbxf6+ Kh5 23.Qg5+
____________________

FEN: 1q1r3k/3P1pp1/ppBR1n1p/4Q2P/P4P2/8/5PK1/8 w - - 0 1 

Stockfish_21010817:  ---------------------------------------------------------------------------
 52/76  1:28:44  128,623,864k  24,161k  +8.54  1.Kh3 Kg8 2.Qe7 Qc7 3.Kg2 Kh8 4.Kg1 Kg8 5.Rd3 Qb8 6.Rc3 Rf8 7.Bd5 Nxd7 8.Qxd7 Qxf4 9.Rc8 Qf6 10.Rxf8+ Kxf8 11.Qc8+ Ke7 12.Qxa6 Qg5+ 13.Bg2 Qc1+ 14.Qf1 Qg5 15.Qc4 Qf6 16.Qe4+ Kf8 17.Qa8+ Ke7 18.Qb7+ Kf8 19.Qe4 Qc3 20.Bf3 Qc1+ 21.Kg2 Qg5+ 22.Qg4 Qc5 23.Qg3 Ke7 24.Qxg7 Qd6 25.Qg3 Qd4 26.Bc6 Kf8 27.Qa3+ Kg7 28.Qf3 Qc5 29.Bd5 Qe7 30.Qg3+ Kh7 31.Kh2 Kh8 32.Qf4 Kg7 33.Bf3 Qc5 34.Kg2 Qe7 35.Qg3+ Kf8 36.Bd5 Qd7 37.Qf3 Kg8 38.Bc4 Qe7 39.Qg4+ Kf8
 52/79  1:28:44  128,623,864k  24,161k  +8.57  1.Qe7 Ng8 2.Qe5 Nf6 3.Kf3 Kg8 4.Qe7 Qc7 5.Kg2 Kh8 6.Kg1 Kg8 7.Rd3 Qb8 8.Rc3 Rf8 9.Bd5 Nxd7 10.Qxd7 Qxf4 11.Rc8 Qf6 12.Rxf8+ Kxf8 13.Qc8+ Ke7 14.Qxa6 Qg5+ 15.Bg2 Qc1+ 16.Qf1 Qg5 17.Qc4 Qf6 18.Qe4+ Kf8 19.Qa8+ Ke7 20.Qb7+ Kf8 21.Qe4 Qc3 22.Bf3 Qc1+ 23.Kg2 Qg5+ 24.Qg4 Qc5 25.Qg3 Ke7 26.Qxg7 Qd6 27.Qg3 Qd4 28.Qc7+ Kf6 29.Kg3 Kg7 30.Qf4 Qc5 31.Kg2 Qe7 32.Qf5 Kf8 33.Bd5 Kg7 34.Qg4+ Kf8 35.Qf4 Kg7 36.Kh3 Qd7+ 37.Qg4+ Qxg4+ 38.Kxg4 Kf8 39.Bc4 f5+ 40.Kg3
 52/76  1:28:44  128,623,864k  24,161k  +8.57  1.Kg1 Kg8 2.Qe7 Qc7 3.Rd3 Qb8 4.Rc3 Rf8 5.Bd5 Nxd7 6.Qxd7 Qxf4 7.Rc8 Qf6 8.Rxf8+ Kxf8 9.Qc8+ Ke7 10.Qxa6 Qg5+ 11.Bg2 Qc1+ 12.Qf1 Qg5 13.Qc4 Qf6 14.Qe4+ Kf8 15.Qa8+ Ke7 16.Qb7+ Kf8 17.Qe4 Qc3 18.Bf3 Qc1+ 19.Kg2 Qg5+ 20.Qg4 Qc5 21.Qg3 Ke7 22.Qxg7 Qd6 23.Qg3 Qd4 24.Qc7+ Kf6 25.Kg3 Kg7 26.Qf4 Qc5 27.Kg2 Qe7 28.Kh2 Qc5 29.Kg3 Qe7 30.Kg2 Qc5 31.Be4 Qxh5 32.Bf3 Qg6+ 33.Qg3 Qxg3+ 34.Kxg3 Kh7 35.Be2 b5 36.Bxb5 f6 37.Bd3+ Kg7
 52/86  1:28:44  128,623,864k  24,161k  +8.68  1.Kf3 Kg8 2.Qe7 Qc7 3.Kg2 Kh8 4.Kg1 Ng8 5.Qe5 Nf6 6.Re6 Rxd7 7.Re8+ Ng8 8.Rxg8+ Kxg8 9.Qe8+ Kh7 10.Qxd7 Qxf4 11.Kg2 b5 12.a5 b4 13.Bf3 g6 14.hxg6+ Kxg6 15.Qd3+ Kg7 16.Be2 Kh8 17.Qd5 Qf6 18.Qc5 Qd8 19.Qxb4 Qg5+ 20.Bg4 Qd5+ 21.Bf3 Qg5+ 22.Kf1 Qc1+ 23.Qe1 Qb2 24.Qe8+ Kg7 25.Kg2 Qf6 26.Qd7 Kf8 27.Qc8+ Kg7 28.Qg4+ Kf8 29.Qh5 Qg7+ 30.Kh3 Qf6 31.Kh2 Ke8 32.Kg2 Qe6 33.Qg4 Qf6 34.Qc8+ Ke7 35.Qc5+ Kd8 36.Qd5+ Ke8 37.Qc6+ Qxc6 38.Bxc6+ Kd8 39.Bb7 Kc7 40.Bxa6
---------------------------------------------------------------------------
 53/72  1:50:39  163,223,386k  24,586k  +8.82  1.Qe7 Qc7 2.Kg1 Kg8 3.Rd3 Qb8 4.Rc3 Rf8 5.Bd5 Kh7 6.Be4+ Kg8 7.Bf5 Nxd7 8.Qxd7 Qxf4 9.Rc8 Qh4 10.Bd3 Qf6 11.Bxa6 g6 12.hxg6 Qxg6+ 13.Kh2 Qe4 14.Rxf8+ Kxf8 15.Qc8+ Kg7 16.Qc3+ Kg8 17.Qg3+ Kf8 18.Qa3+ Kg7 19.Bb5 Qh4+ 20.Qh3 Qf6 21.Qg4+ Kf8 22.Kg2 Qe5 23.Qc8+ Kg7 24.Qh3 Qd5+ 25.Qf3 Qe6 26.Bd3 Kf8 27.Be4 Kg7 28.Bd5 Qd7 29.Bc4 Kf8 30.Qf4 Kg7 31.Qg3+ Kh8 32.Kh2 Qf5 33.Bd3 Qf6 34.Be4 Qd4 35.Bc6 Qc5
 53/68  1:50:39  163,223,386k  24,586k  +8.82  1.Kg1 Kg8 2.Qe7 Qc7 3.Rd3 Qb8 4.Rc3 Rf8 5.Bd5 Kh7 6.Be4+ Kg8 7.Bf5 Nxd7 8.Qxd7 Qxf4 9.Rc8 Qh4 10.Bd3 Qf6 11.Bxa6 g6 12.hxg6 Qxg6+ 13.Kh2 Qe4 14.Rxf8+ Kxf8 15.Qc8+ Kg7 16.Qc3+ Kg8 17.Qg3+ Kf8 18.Qa3+ Kg7 19.Bb5 Qh4+ 20.Qh3 Qf6 21.Qg4+ Kf8 22.Kg2 Qe5 23.Qc8+ Kg7 24.Qh3 Qd5+ 25.Qf3 Qe6 26.Bd3 Kf8 27.Be4 Qd7 28.Bd5 Kg7 29.Qc3+ Kg8 30.Qd4 Kf8 31.Qb4+ Kg8 32.Bf3 Qd3 33.Qxb6
 53/82  1:50:39  163,223,386k  24,586k  +8.82  1.Kf3 Kh7 2.Qe7 Ng8 3.Qe4+ Kh8 4.Qe5 Nf6 5.Kg2 Kg8 6.Qe7 Qc7 7.Kf1 Kh8 8.Kg1 Kg8 9.Rd3 Qb8 10.Rc3 Rf8 11.Bd5 Kh7 12.Be4+ Kg8 13.Bf5 Nxd7 14.Qxd7 Qxf4 15.Rc8 Qh4 16.Bd3 Qf6 17.Bxa6 g6 18.hxg6 Qxg6+ 19.Kh2 Qe4 20.Rxf8+ Kxf8 21.Qc8+ Kg7 22.Qc3+ Kg8 23.Qg3+ Kf8 24.Qa3+ Kg7 25.Bb5 Qh4+ 26.Qh3 Qf6 27.Qg4+ Kf8 28.Kg2 Qe5 29.Qc8+ Kg7 30.Qh3 Qd5+ 31.Qf3 Qe6 32.Kh2 Kh7 33.Be2 Qe5+ 34.Kg2 Qe6 35.Kg1 Kh8 36.Qg4 Qd6 37.Kg2 Qd5+ 38.Bf3 Qd6 39.Qe4 Qf6 40.Bh5
 53/84  1:50:39  163,223,386k  24,586k  +14.23  1.Rxf6 Qxe5 2.fxe5 Rxd7 3.e6 Rd6 4.e7 gxf6 5.e8Q+ Kg7 6.Kf3 Rd3+ 7.Kf4 Rd4+ 8.Ke3 Rd6 9.Qd7 Rxd7 10.Bxd7 Kf8 11.Kf3 f5 12.Bxf5 Ke8 13.Bc8 a5 14.Ba6 Ke7 15.Bc4 Kd6 16.Kf4 b5 17.Bxb5 Kd5 18.Kf5 Kd4 19.Kf6 Ke4 20.Kxf7 Kf5 21.Kg7 Kg5 22.Bc4 Kg4 23.Kxh6 Kf3 24.Bb5 Ke4
Up Topic The Rybka Lounge / Test Positions / 2 problems in Hard-Talkchess-2020

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