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### Hard Puzzles found on Gameknot

Posted: **Fri Jun 19, 2020 11:21 am**

by **Nordlandia**

User Moremover on chess.com claims that many of the Puzzles are unsolved.

May be worth to examine further

https://gameknot.com/chess-puzzles.pl?s ... de&m=0&s=9

### Re: Hard Puzzles found on Gameknot

Posted: **Fri Jun 19, 2020 1:52 pm**

by **MOBMAT**

This site doesn't provide the FEN of the positions, but I submitted a request that they include the FEN.

This appears to be a site for "hoomans", not engines, so I'm not sure they will really care.

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 3:30 am**

by **Dann Corbit**

Of the 1270 problems on the gameknot site, these are the ones I did not solve yet:

Code: Select all

```
6rr/2q2pkp/2pb1nn1/4B2Q/3P1P2/4N3/2BR1RP1/7K w - - dm 9;
8/1B2N3/2p4p/1b1p1K1k/pRQpP1p1/1q3pP1/Rbrn4/Q4n2 w - - dm 10;
8/8/p5p1/rp3pBk/1p3P1p/pP1p1Rb1/B2P2P1/7K w - - dm 11;
rk4r1/1pn3b1/pN1pp1b1/1p2p1B1/4P3/R1Q2P2/PPP5/1K6 w - - dm 11;
5N2/5p2/BBpNpK2/P2kP3/2p2P2/2p5/2pPbPP1/2r3nn w - - dm 11;
8/5p2/5N2/8/K3nN1p/1p3k2/1Pp2prR/n1B2bbB w - - dm 12;
5b2/p5p1/4p1P1/1p2Rn1p/1P1k1PRn/PK6/3NP1P1/8 w - - dm 12;
7n/2B1p3/R2p3p/1p1Pk2N/4Pb2/2pP3b/P1PRN1n1/K7 w - - dm 12;
6B1/1p2p3/p2pp1pK/N3k3/1R4p1/8/1pP4n/4N3 w - - dm 12;
N7/pp6/1b6/1p1p4/1BkP4/KpPN2Q1/p3q3/rb6 w - - dm 12;
2N5/1pp5/1b6/1p1p4/1BkP4/KpPN2Q1/p3q3/rb6 w - - dm 12;
7N/5pp1/6b1/4p1p1/4PkB1/1Q2NPpK/3q3p/6br w - - dm 12;
8/4Kp2/2p1nR2/2PkP3/4nP1p/BP2P1pr/1p2P1p1/1N4Nb w - - dm 13;
8/3pK3/2p1nR2/2PkP3/4nP1p/BP2P1pr/1p2P1p1/1N4Nb w - - dm 13;
8/4pKpp/2R1Q1rk/6pb/8/5N1P/p2R4/r7 w - - dm 13;
6r1/1p1R4/k1b4b/P1R3pr/BB3pp1/2P5/KP5p/8 w - - dm 14;
8/1p1p1p2/nP1P1P2/8/2B2Pp1/p1B3P1/rrp3PK/kbR5 w - - dm 14;
4B1b1/2p1B1Kp/4p2p/nP1k3N/1P4P1/2pPP1pP/pb2n3/8 w - - dm 14;
6r1/1p1R4/k1b4b/P5pr/BBR2pp1/2P5/KP5p/8 w - - dm 14;
5b1r/6p1/3p1rQn/8/N1kN1K2/2P1p3/2Bn2R1/8 w - - dm 15;
3K1b2/2B1pppB/4P3/1p6/k1NP2p1/3R3b/p3P3/8 w - - dm 15;
R7/1p1p1p2/n2pbP1N/p2p1p2/P2P1P2/4p3/2K1N3/k7 w - - dm 15;
6n1/r1p2p2/1pNp1p2/6pK/2BBk1p1/6P1/1p3P2/3N4 w - - dm 15;
2n5/3p1Kp1/6Nn/2P1Pk2/3R4/5Bp1/2r5/2B1b3 w - - dm 15;
8/4p1K1/N2kppN1/8/B1p1P3/2Pn1RP1/2pp1P2/4b3 w - - dm 16;
2b2n2/pp1pKp2/kN1Pn1r1/1p6/q2p4/1Q2p3/2Bp1r2/1R2B3 w - - dm 16;
n5nr/K6p/1p3N2/2kp2Pp/3N1P2/PpB1P3/1Pp5/4R3 w - - dm 16;
8/8/6pp/6kq/2p1P1pb/3pN1p1/3P1NP1/B3K2R w K - dm 16;
5K2/2p3p1/Q2r2P1/3P4/1P5B/7p/pp4pr/kn4Rb w - - dm 17;
8/4Bp2/3N1P2/3kN2b/1p1P4/2n1K1p1/qQP1n1Pp/5B2 w - - dm 17;
3n4/qr3R2/1p1N1pP1/7P/3K2nB/N7/Bp1k2p1/R2b2r1 w - - dm 17;
8/p3B1Kp/4RRb1/1Np1n3/2Bpk1pP/q7/4P3/b1r5 w - - dm 19;
8/3Br3/7p/8/pr1Bp3/Kpp3q1/7k/3Q4 w - - dm 19;
5q1r/2pBRp2/Q1p4P/2ppp2K/2rkp3/N7/1P5b/2N5 w - - dm 20;
B7/5N2/7Q/2p3B1/5N2/1ppn4/pkp1K3/bb2n3 w - - dm 20;
8/ppnBKR2/1p2p3/2Pk1b2/P4Rp1/3N4/1p3p2/8 w - - dm 20;
2n5/4nN2/K1p5/2p5/2P3BP/3kBp2/2pPppp1/3N2b1 w - - dm 21;
1B6/5Rp1/1p3prp/1P3Pkr/2p3Pb/1R1n1Pp1/3p2P1/3K4 w - - dm 21;
8/7p/1QppB3/2r5/2N1pN1B/4PkP1/5p2/Kn1b1r2 w - - dm 22;
4R1b1/r2p1pP1/B1p2k2/3p3K/1pP2P2/1P2B2p/4Nppb/8 w - - dm 23;
2b1n3/3nKp1p/4p2k/p7/1p2pN1P/2p1B1R1/3p1P2/q1r5 w - - dm 24;
4K3/2p2p2/2P2P2/8/1p3p1R/2R1prp1/1P2prp1/4Bbkn w - - dm 24;
2n5/p1K1pp2/1N4p1/p3k1P1/1PPbp2B/1p1pP1Pr/P1NP4/4n3 w - - dm 24;
8/2ppK1p1/2pn2pb/p2b2pk/3R2Rn/B2PP2P/P7/5B2 w - - dm 24;
7R/p7/Ppp1B1p1/R1n1B2r/4kP1P/3p1p1P/3prp2/3Kb2N w - - dm 25;
k4n2/ppp1NK1p/2pB2p1/1Q6/3p4/4rpb1/RP3rP1/4q1nb w - - dm 27;
B7/3N1pp1/8/2Bn2P1/2kNpP2/P3Pp1p/1p2pP2/1b2K1n1 w - - dm 28;
8/1ppr4/br6/1pkp4/2p1Qp2/KPp2p2/B1PP1P2/8 w - - dm 62;
4Q1R1/1pRp1rbp/1Pn2k1q/2P2prb/5Pp1/3p1pP1/3P1P1K/6B1 w - - dm 63;
```

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 3:36 am**

by **Dann Corbit**

Update:

Solutions for the top two:

bm Qh6+; ce 32750; dm 9; pv Qh6+ Kxh6 Nf5+ Kh5 g4+ Nxg4 Rh2+ Nxh2 Bd1+ Ng4 Rh2+ Nh4 Rxh4+ Kg6 Rh6+ Nxh6 Nh4#;

bm Qaxf1; ce 32748; dm 10; pv Qaxf1 Nxf1 Qxf1 Bxf1 Ng8 d3 e5 Bxe5 Nf6+ Bxf6 Bxc6 Rxc6 Rh2+ Bh3 Rxh3+ gxh3 Rh4+ Bxh4 g4#;

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 4:06 am**

by **Dann Corbit**

Next one:

bm Rxg3; ce 32746; dm 11; pv Rxg3 hxg3 Kg1 Kg4 Kf1 Kh5 Ke1 Kg4 Kd1 Kh5 Kc1 Kg4 Kb1 Ra4 bxa4 b3 Bxb3 a2+ Ka1 b4 Bd1#;

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 4:53 am**

by **MOBMAT**

There appears to be a lot more than 1200 on the site.

did you solve this one? I tried multiple engines and none of them found it (given my hardware/time).

I think the correct move is Nd5 and mate in 16

Puzzle #240957

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 6:38 am**

by **peter**

MOBMAT wrote: â†‘Sat Jun 20, 2020 4:53 am

There appears to be a lot more than 1200 on the site.

did you solve this one? I tried multiple engines and none of them found it (given my hardware/time).

I think the correct move is Nd5 and mate in 16

Puzzle #240957

After some Forward Backward of different lines and follow up pondering in multi variant mode, here at depth 43/73:

8/8/6pp/6kq/4P1pb/4N1p1/3P1NP1/B3K2R w K - 0 1

Analysis by Crystal 040620 64 POPCNT:

1. +- (#21): 27.Nd5 gxf2+ 28.Kf1 g3 29.Bf6+ Kg4 30.Rxh4+ Qxh4 31.Bxh4 g5 32.Bxg3 Kxg3 33.e5 Kg4 34.e6 Kf5 35.e7 Ke6 36.e8Q+ Kxd5 37.Qh5 Ke6 38.Qxh6+ Kd5 39.Kxf2 g4 40.Qf6 g3+ 41.Ke3 Kc5 42.Qe6 Kb4 43.Qc6 Ka5 44.Kd3 Kb4 45.Qb6+ Ka4 46.Kc3 Ka3 47.Qb3#

2. +- (#22): 27.Nfxg4 Kf4 28.Be5+ Kxe4 29.Ke2 Qxg4+ 30.Nxg4 Bd8 31.Bf6 Bxf6 32.Nxf6+ Kf5 33.Rxh6 Kxf6 34.d4 Ke6 35.Rh1 Kd6 36.Rd1 Kd5 37.Rd2 Kc6 38.d5+ Kd6 39.Rd1 g5 40.Rd2 Kc7 41.d6+ Kd7 42.Rd3 Ke6 43.d7 Kf5 44.d8Q Ke6 45.Rd5 Kf7 46.Rd6 g4 47.Qc7+ Kf8 48.Rd8#

3. +- (#22): 27.Be5 gxf2+ 28.Kf1 Bg3 29.Rxh5+ gxh5 30.Bxg3 h4 31.Be5 Kg6 32.Bc7 Kh5 33.Nd5 Kg6 34.Kxf2 h3 35.gxh3 gxh3 36.Nb6 Kg5 37.d4 h5 38.d5 Kg4 39.Bh2 Kg5 40.d6 Kf6 41.d7 Ke7 42.Bc7 h2 43.d8Q+ Kf7 44.Be5 h1N+ 45.Kf3 Nf2 46.Qf6+ Ke8 47.Qe6+ Kd8 48.Qd7#

4. +- (#22): 27.Ke2 gxf2 28.Be5 Bg3 29.Rxh5+ gxh5 30.Bxg3 h4 31.Bc7 f1Q+ 32.Kxf1 h3 33.gxh3 gxh3 34.Nc4 h5 35.d4 Kg4 36.Kf2 h2 37.Bxh2 h4 38.Nb6 Kg5 39.d5 Kf6 40.d6 h3 41.d7 Ke7 42.Bc7 Kf7 43.d8Q h2 44.Be5 Kg6 45.Qf6+ Kh5 46.Bf4 Kg4 47.Qf5+ Kh4 48.Bg3#

5. +- (#34): 27.Kf1 Kf4 28.Nd5+ Qxd5 29.exd5 Bg5 30.Nd3+ Ke4 31.Ne5 Kxd5 32.Ke2 Kc5 33.Nxg6 Kd5 34.Ne5 Ke6 35.Nxg4 Kd7 36.Nxh6 Be7 37.Ng4 Bf8 38.Be5 Kc6 39.Bxg3 Kb5 40.Ne5 Bd6 41.Rh7 Bc5 42.Bf2 Bxf2 43.Kxf2 Kc5 44.Rh5 Kd6 45.Rh6+ Kc5 46.Nd3+ Kb5 47.Ke2 Ka5 48.Nf2 Ka4 49.Rh5 Ka3 50.Ng4 Kb2

6. +- (#38): 27.Nfd1 Kf4 28.Nd5+ Kxe4 29.N1e3 Bg5 30.Ke2 Bxe3 31.Rxh5 gxh5 32.Nxe3 h4 33.Nxg4 h5 34.Nf6+ Kf4 35.Nxh5+ Kf5 36.Kf3 Kg6 37.Kg4 Kf7 38.Ng7 Ke7 39.Kxh4 Kf7 40.Kxg3 Kf8 41.Nf5 Kf7 42.Kf3 Ke6 43.Nh6 Ke7 44.Be5 Kd8 45.Bg3 Kc8 46.Bh4 Kc7 47.g4 Kd7 48.Ke3 Ke8 49.Kf2 Kf8 50.Bf6 Ke8 51.g5 Kd7 52.g6

After that I went back the first one line again, no way of "solution" with 16 moves to mate to be found, Crystal keeps the #21 for best.

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 7:25 am**

by **Dann Corbit**

I have Nfxg4 as dm 21.

Quite frankly, this position is an illustration of what is wrong with the problem set.

There are lots of solutions, and typically, there is an obvious move that wins easily. Scored as wrong, of course.

But there is some other esoteric move that wins more quickly.

A move that wins wins. Winning more quickly does not garner more points.

A move that wins more quickly is in some artistic way better, but in game theoretic view it is not better.

This test set is loaded with positions like that.

I guess that I only collected the positions that people have actually tried. My scraper is not that intelligent.

Meanwhile, the site will be flunking people for obvious winning moves.

Sweaty pools of lameness will lamely drown the lame in their lame lameness.

No, really, they will.

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 7:47 am**

by **peter**

Or even19 only, which would be shorter than my line after Nd5 above again. After an extra- Backward of the Nfxg4- line:

8/8/6pp/6kq/4P1pb/4N1p1/3P1NP1/B3K2R w K - 0 1

Analysis by MateFinder 050320 64:

27.Nfxg4 Kf4 28.e5 Be7 29.Rxh5 gxh5 30.Nd5+ Kf5 31.Nxe7+ Ke6 32.Ng6 hxg4 33.Bb2 h5 34.Nf4+ Ke7 35.Ba3+ Ke8 36.e6 h4 37.Nh5 h3 38.Nf6+ Kd8 39.e7+ Kc7 40.e8Q hxg2 41.Nd5+ Kb7 42.Qd7+ Ka6 43.Qc6+ Ka7 44.Qb6+ Ka8 45.Nc7#

+- (#19) Depth: 48/38 00:00:00 505kN

### Re: Hard Puzzles found on Gameknot

Posted: **Sat Jun 20, 2020 1:03 pm**

by **MikeGL**

Here's the possible Mate in 63 and also M62 solutions (using SF and manual analysis)

There's a glitch in M62 puzzle. My interface keeps on reporting 50-move-rule draw, because there's no capture.

Maybe that, or there is a more efficient mate reaching M62 with captures somewhere.