Amazing test position

[Robert Flesher]

[d]8/8/7p/3KNN1k/2p4p/8/3P2p1/8 w - -




How do you evaluate the position ?

[jdart]

White is much worse, unless there is a clever draw.

Nf3 and Ng7+ are the obvious tries. But without tablebases, I am not showing either one with a draw score, after 5+ minutes.

[pacifist]

Fortress with Nxh4 and Nf3. Engines don't find it?

[Robert Flesher]

Fortress with Nxh4 and Nf3. Engines don't find it?

Bingo!


Kc6!! then as you said the fortress!

[Robert Flesher]

White is much worse, unless there is a clever draw.

Nf3 and Ng7+ are the obvious tries. But without tablebases, I am not showing either one with a draw score, after 5+ minutes.

1. Kc6 g1=Q 2. Nxh4 Qe1 3. Nhf3!! (fortress) c3 4. dxc3 Qxc3+
Draw!

Lots of progress can me still made with chess engines.

[Dann Corbit]

White is much worse, unless there is a clever draw.

Nf3 and Ng7+ are the obvious tries. But without tablebases, I am not showing either one with a draw score, after 5+ minutes.

1. Kc6 g1=Q 2. Nxh4 Qe1 3. Nhf3!! (fortress) c3 4. dxc3 Qxc3+
Draw!

Lots of progress can me still made with chess engines.

I think that Ng7+ also holds.

The score is bad, but I don't think that the opponent can make progress.

Here is a pv:
32 08:59 3.475.735,865 6.446.000 -3.48 Nf5g7+ Kh5g5 Ne5f3+ Kg5g4 Kd5e4 h4h3 Ng7f5 g2g1Q Nf5xh6+ Kg4h5 Nf3xg1 h3h2 Ng1f3 h2h1Q Nh6f5 Qh1b1+ Ke4f4 Qb1b4 Nf5d4 Qb4f8+ Nd4f5 Qf8f6 Kf4e4 Qf6g6 Ke4e5 Qg6g2 Nf5d4 Qg2g8 Nd4f5 Qg8b8+ Ke5e4 Qb8b7+ Ke4f4 Qb7d5 Nf5e3 Qd5d6+ Kf4e4 Qd6g6+ Ke4f4 Qg6h6+ Kf4e4 Qh6g6+

[George Tsavdaris]

White is much worse, unless there is a clever draw.

Nf3 and Ng7+ are the obvious tries. But without tablebases, I am not showing either one with a draw score, after 5+ minutes.

1. Kc6 g1=Q 2. Nxh4 Qe1 3. Nhf3!! (fortress) c3 4. dxc3 Qxc3+
Draw!

Lots of progress can me still made with chess engines.

Yes this is the famous Behting study.

[Robert Flesher]

White is much worse, unless there is a clever draw.

Nf3 and Ng7+ are the obvious tries. But without tablebases, I am not showing either one with a draw score, after 5+ minutes.

1. Kc6 g1=Q 2. Nxh4 Qe1 3. Nhf3!! (fortress) c3 4. dxc3 Qxc3+
Draw!

Lots of progress can me still made with chess engines.

I think that Ng7+ also holds.

The score is bad, but I don't think that the opponent can make progress.

Here is a pv:
32 08:59 3.475.735,865 6.446.000 -3.48 Nf5g7+ Kh5g5 Ne5f3+ Kg5g4 Kd5e4 h4h3 Ng7f5 g2g1Q Nf5xh6+ Kg4h5 Nf3xg1 h3h2 Ng1f3 h2h1Q Nh6f5 Qh1b1+ Ke4f4 Qb1b4 Nf5d4 Qb4f8+ Nd4f5 Qf8f6 Kf4e4 Qf6g6 Ke4e5 Qg6g2 Nf5d4 Qg2g8 Nd4f5 Qg8b8+ Ke5e4 Qb8b7+ Ke4f4 Qb7d5 Nf5e3 Qd5d6+ Kf4e4 Qd6g6+ Ke4f4 Qg6h6+ Kf4e4 Qh6g6+

Wow Dan! this also looks pretty convincing, very nice!

[Arpad Rusz]

I have analysed that study few years ago and then it seemed sound (no double solution, only 1.Kc6!! draws).

C. Behting
Bohemia - 1906
2/5.Pr.
[d]8/8/7p/3KNN1k/2p4p/8/3P2p1/8 w - -
Draw

1.Kc6!! mutual zugzwang
[1.Nxh4? Kxh4! (1...g1Q? 2.Nhf3=) 2.Nf3+ Kg3 3.Ng1 h5-+;
1.Nf3? h3 2.Ke4 h2 3.Ng3+ Kg4 4.Nxh2+ Kxg3 5.Nf3 Kf2!-+ (5...h5? 6.Ke3 h4 7.Ng1 h3 8.Ne2+ Kh2 9.Kf2 Kh1 10.Ng3+ Kh2 11.Ne2 positional draw) ;
1.Ng7+? Kg5 2.Nf3+ (2.Ne6+ Kf6-+) 2...Kg4 (2...Kf4? 3.Ng1 Kg4 4.Ne6 h3 5.Nxh3 Kxh3 6.Nf4+=) 3.Nh2+ Kf4!-+ (3...Kg3? 4.Nf5+ Kf2 (4...Kxh2 5.Nxh4 g1Q 6.Nf3+ Kg2 7.Nxg1 Kxg1 8.Kxc4=) 5.Ng4+ Ke2 6.Nd4+ Kxd2 7.Kxc4 h5 8.Nf3+ Ke2 9.Ngh2=) ;
1.Ng3+? hxg3 2.Nf3 Kg4 3.Ke4 h5-+]
1...g1Q [1...h3 2.Ng3+ Kh4 3.Ne2 h2 4.Nf3+ Kh3 5.Nxh2=] 2.Nxh4! Qh1+ 3.Nhf3 positional draw - blockade

[Robert Flesher]

I have analysed that study few years ago and then it seemed sound (no double solution, only 1.Kc6!! draws).

C. Behting
Bohemia - 1906
2/5.Pr.
[d]8/8/7p/3KNN1k/2p4p/8/3P2p1/8 w - -
Draw

1.Kc6!! mutual zugzwang
[1.Nxh4? Kxh4! (1...g1Q? 2.Nhf3=) 2.Nf3+ Kg3 3.Ng1 h5-+;
1.Nf3? h3 2.Ke4 h2 3.Ng3+ Kg4 4.Nxh2+ Kxg3 5.Nf3 Kf2!-+ (5...h5? 6.Ke3 h4 7.Ng1 h3 8.Ne2+ Kh2 9.Kf2 Kh1 10.Ng3+ Kh2 11.Ne2 positional draw) ;
1.Ng7+? Kg5 2.Nf3+ (2.Ne6+ Kf6-+) 2...Kg4 (2...Kf4? 3.Ng1 Kg4 4.Ne6 h3 5.Nxh3 Kxh3 6.Nf4+=) 3.Nh2+ Kf4!-+ (3...Kg3? 4.Nf5+ Kf2 (4...Kxh2 5.Nxh4 g1Q 6.Nf3+ Kg2 7.Nxg1 Kxg1 8.Kxc4=) 5.Ng4+ Ke2 6.Nd4+ Kxd2 7.Kxc4 h5 8.Nf3+ Ke2 9.Ngh2=) ;
1.Ng3+? hxg3 2.Nf3 Kg4 3.Ke4 h5-+]
1...g1Q [1...h3 2.Ng3+ Kh4 3.Ne2 h2 4.Nf3+ Kh3 5.Nxh2=] 2.Nxh4! Qh1+ 3.Nhf3 positional draw - blockade

If the key is to draw, then perhaps there are two solutions