Research idea: the longest middlegame attacks

Discussion of anything and everything relating to chess playing software and machines.

Moderator: Ras

LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Research idea: the longest middlegame attacks

Post by LevyRook »

I'm interested in "the longest non-trivial forced middlegame variations" (for simplicity, most of the time I'll refer to it as "the longest non-trivial middlegame checkmates"). I figured this topic is relevant to computer chess because
  • Such variations can be found in computer games.
  • Such variations can be used for testing engines.
  • Maybe we can even use computers to generate such variations.
Many positions discussed here are completely illegal. But they can be split into smaller puzzles.

Motivation

People love long middlegame attacks. Kasparov's Immortal (~14-move attack), Serper's Immortal (~23-move attack), Polish Immortal (~13-move attack).

However, strangely no one seems to ask how long can such middlegame attacks get. Even though it seems like an important topic about exploring the limits of chess' complexity.

The current length records are all about the endgame (tablebase records) or are in some sense "trivial", using very specific tricks to achieve length (e.g. repeated zugzwang). Such length records have zero traits in common with immortal games.

Defining middlegame and triviality

How do we define a "middlegame"? How do we define "triviality"?

Instead of defining it directly, I think a better approach is to consider parameters which make the length of a checkmate objectively harder to achieve:
  • (P) The amount of pieces on the board.
  • (P) The amount of pieces which make a move in the checkmating variation.
  • (P) The amount of heavy pieces. Rooks and queens.
  • (P) The amount of non-check moves.
  • (P) The size of material disadvantage of the checkmating side.
  • (P) The degree of naturalness of the position.
  • (N) The amount of obvious repetitions.
  • (N) The degree of isolation of pieces. For example, if a piece is 100% isolated from the game forever, it's bad.
As the positive (P) parameters go up and the negative (N) parameters go down, the length of a checkmate becomes objectively harder to achieve. Meaning there becomes objectively less checkmates satisfying such parameters. Also, note that many of those parameters have to be evaluated throughout the entire checkmating variation, not only in the initial position. If a complicated middlegame simplifies into a technically won endgame, the technically won endgame doesn't count as adding length.

So, instead of a single definition of a "non-trivial middlegame checkmate", think about a PARAMETER SPACE we can explore. I know, it's inconvenient that there isn't a single simple definition for the task at hand. But that doesn't make the topic less important. If we care about chess, we should care about the maximal length of middlegame attacks. We should care about DIFFERENT types of length records, not just about 1 or 2 types.

How to research that?

I think there's two main avenues of research.

The first avenue is analyzing computer games. They contain the longest and most sound middlegame attacks. The second avenue is creating arbitrary chess positions.

I'll share some of my puzzles. Then some of the other people's puzzles and some computer games.

My puzzles

Disclaimer: all positions here were verified with 40MB browser Stockfish, sometimes it misses a lot of stuff. I think the positions are valuable even if they have refutations.

Above is a checkmate in 34 moves. At every half-move White is at least 16 points of material down. White never gains material advantage. Queens never get traded off. No piece is forever isolated from the game. Checkmating the Black King requires finding A LOT of completely original moves, no repetitions. Not every White's move is a check or even a capture. The entirety of the checkmate takes place in the "middlegame".

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

qrqqqqqq/qqqqqBqN/qrrPnpqq/Nnr1nppr/qrBNPq1b/rP1B1p1k/pPQPQQRP/nNBNKR1b w - - 1 1

Above is a checkmate in 32 moves. At every half-move White is at least 126 points of material down. If you want to try guessing it move by move: https://lichess.org/study/hBcBtt33. Click "reveal the solution" to reveal the next move, it doesn't reveal the whole thing.
Above is a fragment of my "checkmate in 42 moves" puzzle. White is never up material. Most of the half-moves White is at least 3 points down.

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

rn2Q1rb/qq1n1b2/Nqp3Bk/1q2Pppq/RprpR1rb/brpP1rQ1/qPPN2PQ/rbBRK2Q w - - 6 1

Above is a checkmate in 43 moves. At every half-move White is at least 26 points of material down. There's one fixable flaw though: White can find a shorter checkmating variation on the 3rd move.

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

qRnrnrkn/rb1q1bqp/Rqnp1Qbq/nR2QnQP/rR1P1BN1/BNPQpb1R/qPB2P2/qNNNK2n w - - 3 1

Position above shows what a non-trivial checkmate in 52 moves could look like. Unfortunately the position has multiple flaws without any obvious fix. White has shorter checkmates (10. Rf5+, 12. Bf6) and Black has a draw (25. ... Rxg7).

Others' compositions

This composition by Steffen Slumstrup Nielsen has the following properties. White is at least down a piece for the first 26 moves. At least two heavy pieces are on the board for the first 21 moves. It IS a long non-trivial attack, despite being closer to an endgame.

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

8/7Q/2r1p3/2rkr3/2rrr2Q/7K/8/8 w - - 0 1

This composition by Philip Bondarenko is unique, because it shows the longest checkmate given the biggest material disadvantage (13 points of material) with the maximal freedom of movement (all Black's rooks are centralized in a completely open position). It's "trivial" in terms of all moves being checks and there being an obvious repeating pattern, but it maximizes other non-trivial parameters.

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

b2b1Rqb/Nnp2brR/1pN1N1Pq/n2K4/pP6/2k1Pp1n/Rpp3br/rbBbrrqq w - - 0 1

Above is a bastardized version of a composition by Otto Blathy and Heinrich Meyer. White gives checkmate in 45 moves. Being at least 67 points down at every half-move. However, it's "trivial" in terms of all moves being checks and there being an obvious repeating pattern.

The composition above is unique, because despite having a giant material advantage White needs ~24 moves to get a dominating position.

In this puzzle by David Zimbeck White launches an insane sacrificial attack. In some variations White takes slightly more than 31 moves to gain material advantage. The puzzle is not based on a repeating pattern.


Computer games

In the game Stoofvlees vs. Igel, there happened a non-trivial 21 move sequence. Throughout which White were down at least 5 points of material (not every half-move, but every move), at least 2 queens and 5 heavy pieces overall remained on the board.

In the game Torch vs. Leela Chess 0, there happened a non-trivial 20 move sequence.

So, even with computer games finding a 25+ move attack down material is not easy. But my knowledge of computer chess is extremely limited.

Conclusions and Resources

Here are Lichess studies with the positions I talked about:

https://lichess.org/study/sTon08Mb

https://lichess.org/study/XZjpjz0c

Even illegal positions don't make creating a long non-trivial middlegame checkmate easy.

The longest non-trivial checkmate may be only 50-60 moves long. We never gonna know where a hard ceiling will hit, but it's definitely got to be less than 100 moves.

Finding "the longest non-trivial middlegame draw" has to be more complicated than finding the longest non-trivial middlegame checkmate.

Many positions with long (30+ moves) non-trivial checkmates were built from positions from real games. It gives many positions a kind of unique and recognizable look. Underneath all the insanity those positions look "vaguelly typical".

What you can do without much effort

You can post here a legal middlegame position with a 10+ checkmate (the longer, the better). The entirety of the checkmate doesn't have to be non-trivial (because we can make it non-trivial later, by modifying the position). I could try expanding it (by making the position illegal). That's how I created most of my puzzles, the original positions came from my bullet games. And one of the positions I was lucky to find on Reddit.
User avatar
Look
Posts: 382
Joined: Thu Jun 05, 2014 2:14 pm
Location: Iran
Full name: Mehdi Amini

Re: Research idea: the longest middlegame attacks

Post by Look »

Hi,

Welcome to talkchess.

[...]
Disclaimer: all positions here were verified with 40MB browser Stockfish, sometimes it misses a lot of stuff.
[...]

Use Stockfish in a proper GUI with a much higher hash and processing power. Single core if you want deterministic results.
Farewell.
LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks

Post by LevyRook »

Hi, Look! Often I don't have much computing power.

I know that I could go at much greater lengths to verify the positions, but I need to know if anybody cares about the topic in the first place (and if somebody does care, they may have much greater ability to verify the positions).

Unless I'm wrong, finding even flawed positions of such kind isn't easy. So I hope the post contains enough effort and value to start a discussion.
Jouni
Posts: 3621
Joined: Wed Mar 08, 2006 8:15 pm
Full name: Jouni Uski

Re: Research idea: the longest middlegame attacks

Post by Jouni »

SF is not good for mates. Try Huntsman. First position

Analysis by The Huntsman 1:

1.Rxc7+ Kxc7 2.Bh2+ Bd6 3.Bxd6+ Kxd6 4.Rxc6+ Bxc6 5.Qg3+ Kd5 6.Rd1+ Kc5 7.Rc1+ Kb4 8.Ne5 Ka5 9.Bf1 Rd3 10.Qxd3 b5 11.Rxc6 Qxc6 12.Nxc6+ Kb6 13.Qd4+ Kc7 14.Qxa7+ Kxc6 15.Bg2+ Kd6 16.Qa6+ Kd7 17.Qc6+ Ke7 18.f6+ Kd8 19.Qxa8+ Kd7 20.Qa7+ Kc8 21.Bb7+ Kc7 22.Bf3+ Kd8 23.Qb6+ Kd7 24.Qc6+ Kd8 25.Nf4 Re8 26.Qb6+ Kd7 27.Bc6+ Kd6 28.Bxe8+ Ke5 29.Qe3+ Be4 30.Nd3+ Ke6 31.Qb6+ Bc6 32.Qxc6+ Kf5 33.Bd7+ Kg6 34.Ne5#
+- (#34) Depth: 43/67
Jouni
LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks

Post by LevyRook »

Jouni, I see that Huntsman is a specialized version of Stockfish, optimized for finding checkmates. I appreciate the advice.

That said, why bother if nobody cares about or understands the topic? If people don't care, there's no use in finding such positions in the first place.
LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks

Post by LevyRook »

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

q2q1rN1/nn3p1k/rqpb1n1p/qrp5/qp6/qp1b1P1P/1p1Q1P2/nR2KB1R w - - 5 1

Here's (supposedly) a checkmate in 32. At every half-move White is at least 31 points of material down. The intended solution: 1. Bxd3+ Kxg8 2. Rg1+ Ng4 3. Rxg4+ Qg5 4. Rxg5+ Kh8 5. Rh5 Re8+ 6. Kf1 Re3 7. Qxe3 Qf8 8. Rxh6+ Kg8 9. Bh7+ Kh8 10. Bf5+ Kg8 11. Ke2 Bg3 12. Rg1 Qc7 13. Rh7 Qcd6 14. Qg5+ Qg6 15. Bxg6 Qad8 16. Bxf7+ Kxh7 17. Qf5+ Kh8 18. Qh5+ Kg7 19. Rxg3+ Qg5 20. Rxg5+ Kf6 21. Re5 b1=Q 22. Re6+ Kg7 23. Qh6+ Kxf7 24. Rf6+ Ke7 25. Qxf8+ Kd7 26. Rf7+ Ke6 27. Qe7+ Kd5 28. Qg5+ Kd6 29. Qd2+ Ke6 30. Qd7+ Ke5 31. f4+ Ke4 32. f3#

LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks

Post by LevyRook »

Can you help me to confirm or deny that in the following position White has a checkmate in 32 moves?

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

7k/q1PRr1pb/3pN1np/1Pbp1P2/qrp3P1/nPp1BPK1/qbP2NBN/nnBb4 w - - 1 1

Full PGN with the intended solution:

Code: Select all

[Variant "From Position"]
[FEN "7k/q1PRr1pb/3pN1np/1Pbp1P2/qrp3P1/nPp1BPK1/qbP2NBN/nnBb4 w - - 1 1"]

1. Rd8+ (1. c8=Q+ Bg8 2. Rd8 Re8 3. Rxe8 Ne7 4. Nf8 Nxc8 5. Ng6+ Kh7 6. Nf8+ Kh8) 1... Bg8 2. Rxg8+ (2. c8=Q Re8 3. Rxe8 Ne7 4. Nf4 Nxc8 5. Ng6+ Kh7 6. Nf8+ Kh8 7. Ng6+) 2... Kxg8 3. c8=Q+ Nf8 4. Qxf8+ Kh7 5. g5 Rxe6 6. Bh3 Bxc2 (6... g6 7. f6 Re8 8. Qxh6+ Kg8 9. Qxg6+ Kf8 10. Qh5 Qf7 11. Qh8+ Qg8 12. g6 Qxh8 13. Bh6+ Qg7 14. Bxg7+ Kg8 15. f7+ Kxg7 16. fxe8=Q Bxf2+ 17. Kg2 Qa7 18. Bd7 Qxd7 19. Qxd7+ Kxg6 20. Qe6+ Kh7 21. Qf7+ Kh8 22. Ng4 Bxf3+ 23. Qxf3 cxb3 24. Bh6 Bd4 25. Qf8+ Kh7 26. Qf7+ Kh8 27. Nf6 Bxf6 28. Qxf6+ Kg8 29. Qg7#) (6... hxg5 7. fxe6 Qxb5 8. Bf5+ g6 9. e7 gxf5 10. Qxf5+ Kg7 11. Qf8+ Kh7 12. Nfg4 Bxe3 13. Qf7+ Kh8 14. Nf6 Bf4+ 15. Kg2 Qf2+ 16. Kxf2 Qc5+ 17. Kg2 Bxf3+ 18. Nxf3 Qf2+ 19. Kxf2 Be3+ 20. Bxe3 d4 21. e8=Q#) 7. Ne4 Bxe4 8. fxe4 g6 (8... hxg5 9. fxe6 c2 10. Bf5+ g6 11. e7 Qxe7 12. Qxe7+ Bg7 13. Ng4 Bd4 14. Bxd4 Rxb3+ 15. Ne3 Rxe3+ 16. Bcxe3 Qa7 17. Qxa7 Kh6 18. Qxg7+ Kh5 19. Qxg6#) 9. f6 (9. Qxh6+ Kg8 10. f6 Rxe4) 9... Re8 10. Qxh6+ (10. Qxe8 Qxb5 11. Qf8 Qe8 12. Qxe8 Rb8) 10... Kg8 11. Qxg6+ Kf8 12. Qh5 Qf7 13. Qh8+ Qg8 14. g6 (14. Qh6+ Kf7 15. Bf5 Re7) 14... Bxe3 (14... Qxh8 15. Bh6+ Qg7 16. Bxg7+ Kg8 17. f7+ Kxg7 18. fxe8=Q Bf2+ 19. Kg2 Qa7 20. Bh6+ Kxh6 21. Qf8+ Kxg6 22. Bf5+ Kh5 23. Nf3 c2 24. Qe8+ Qf7 25. Qxf7+ Kh6 26. Qg6#) 15. Qh6+ Bxh6 16. Bxh6+ Qg7 17. Bxg7+ Kg8 18. bxa4 (18. f7+ Kxg7 19. fxe8=Q Qa7 20. b6 Rxb6 21. Bd7 Qxd7 22. Qxd7+ Kxg6) 18... Bc1 19. f7+ Kxg7 20. fxe8=Q Qxh2+ 21. Kxh2 Bf4+ 22. Kg2 dxe4 23. Qf7+ Kh6 24. g7 Rb2+ 25. Kg1 Be3+ 26. Kh1 Rf2 27. g8=N+ Kg5 28. Qg7+ Kf4 29. Qg4+ Ke5 30. Qe6+ Kf4 31. Qf5+ Kg3 32. Qg4#
User avatar
Ajedrecista
Posts: 2103
Joined: Wed Jul 13, 2011 9:04 pm
Location: Madrid, Spain.

Re: Research idea: the longest middlegame attacks.

Post by Ajedrecista »

Hello Jim:
LevyRook wrote: Wed Jun 12, 2024 10:22 am Can you help me to confirm or deny that in the following position White has a checkmate in 32 moves?

[...]
Chest 5.2 in normal mode search found a checkmate in 11 moves after 21.- ..., Bf4+, so there could be a chance:

Code: Select all

FEN: 4Q3/6k1/3p2P1/1P1p4/Prp1Pb2/n1p4B/7K/nn6 w - - 1 22

ChestUCI:
FEN: 4Q3/6k1/3p2P1/1P1p4/Prp1Pb2/n1p4B/7K/nn6 w - -   (7+10)
Stellungs-Analyse:  C0/R0/K3/P8/X22   W:1/3
Suche nach Matt in 11 ...  (Hash=64MB)
  11	01:46	  35.884.379	696.040	+M11	Kh2g2
Suche abgeschlossen ...  (Zeit=129.08s)
Matt in 11 gefunden !  (1 Lösung in 02:09)
 11/11	02:13	  89.241.521	691.376	+M11	Kh2g2 d5xe4 Qe8f7+ Kg7h6 g6g7 Rb4b2+ Kg2g1 Bf4e3+ Kg1h1 Rb2f2 g7g8N+ Kh6g5 Qf7g7+ Kg5f4 Qg7g4+ Kf4e5 Qg4e6+ Ke5f4 Qe6f5+ Kf4g3 Qf5g4+
------------

The same with a checkmate in 12 moves after 20.- ..., Qxh2+:

Code: Select all

FEN: 4Q3/6k1/3p2P1/1P1p4/Prp1P3/n1p3KB/7q/nnb5 w - - 0 21

ChestUCI:
FEN: 4Q3/6k1/3p2P1/1P1p4/Prp1P3/n1p3KB/7q/nnb5 w - -   (7+11)
Stellungs-Analyse:  C0/R0/K3/P9/X31   W:1/4
Suche nach Matt in 12 ...  (Hash=512MB)
  12	01:51	  37.184.052	696.108	+M12	Kg3xh2
Suche abgeschlossen ...  (Zeit=110.99s)
Matt in 12 gefunden !  (1 Lösung in 01:50)
 12/12	01:51	  75.727.511	682.291	+M12	Kg3xh2 Bc1f4+ Kh2g2 d5xe4 Qe8f7+ Kg7h6 g6g7 Rb4b2+ Kg2g1 Bf4e3+ Kg1h1 Rb2f2 g7g8N+ Kh6g5 Qf7g7+ Kg5f4 Qg7g4+ Kf4e5 Qg4e6+ Ke5f4 Qe6f5+ Kf4g3 Qf5g4+
------------

The same with a checkmate in 13 moves after 19.- ..., Kxg7:

Code: Select all

FEN: 4r3/5Pk1/3p2P1/1P1p4/Prp1P3/n1p3KB/q6N/nnb5 w - - 0 20

ChestUCI:
FEN: 4r3/5Pk1/3p2P1/1P1p4/Prp1P3/n1p3KB/q6N/nnb5 w - -   (8+12)
Stellungs-Analyse:  C0/R0/K6/P10/X42   W:7/25
Suche nach Matt in 13 ...  (Hash=512MB)
  13	07:11	 186.561.707	511.649	+M13	f7xe8Q
Suche abgeschlossen ...  (Zeit=605.14s)
Matt in 13 gefunden !  (1 Lösung in 10:05)
 13/13	10:08	 321.341.769	531.022	+M13	f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 d5xe4 Qe8f7+ Kg7h6 g6g7 Rb4b2+ Kg2g1 Bf4e3+ Kg1h1 Rb2f2 g7g8N+ Kh6g5 Qf7g7+ Kg5f4 Qg7g4+ Kf4e5 Qg4e6+ Ke5f4 Qe6f5+ Kf4g3 Qf5g4+
Going move by move until the start is unfeasible for me, though. Chest 5.2 even refuses to analyze the start position with 35 pieces.

------------------------

Huntsman found the checkmate in 13 moves in 17 seconds. It also found a checkmate in 16 moves after 16.- ..., Qg7:

Code: Select all

FEN: 4rk2/6q1/3p1PPB/1P1p4/qrp1P3/nPp3KB/qb5N/nn6 w - - 1 17

Huntsman:
Found 145 tablebases
classical evaluation enabled
[...]
 40/32	00:16	  50.992.360	3.053.983	+M16	Bh6xg7+ Kf8g8 b3xa4 Bb2c1 f6f7+ Kg8xg7 f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 Bf4e5 Qe8f7+ Kg7h6 g6g7 Rb4b2+ Kg2f3 Be5xg7 Bh3f5 d5xe4+ Bf5xe4 Rb2f2+ Kf3xf2 Kh6g5 Qf7f5+ Kg5h4 Be4f3 Bg7d4+ Kf2g2 Nb1d2 Qf5g4+
------------

The same with a checkmate in 18 moves after 14.- ..., Bxe3:

Code: Select all

FEN: 4rkqQ/8/3p1PP1/1P1p4/qrp1P3/nPp1b1KB/qb5N/nnB5 w - - 0 15

Huntsman:
Found 145 tablebases
classical evaluation enabled
[...]
 41/38	00:18	  56.929.159	3.022.680	+M18	Qh8h6+ Be3xh6 Bc1xh6+ Qg8g7 Bh6xg7+ Kf8g8 b3xa4 Bb2c1 f6f7+ Kg8xg7 f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 Kg7h6 Qe8f8+ Kh6h5 g6g7 Rb4b2+ Kg2g1 Bf4e3+ Kg1h1 Nb1d2 Qf8f5+ Be3g5 g7g8Q Rb2b1+ Kh1g2 Rb1g1+ Kg2xg1 Nd2f3+ Kg1f2 Kh5h4 Qf5g4+
------------

The same with a checkmate in 20 moves after 12.- ..., Qf7, taking much more time:

Code: Select all

FEN: 4rk2/5q2/3p1P2/1Pbp2PQ/qrp1P3/nPp1B1KB/qb5N/nnB5 w - - 3 13

Huntsman:
Found 145 tablebases
classical evaluation enabled
[...]
 24/42+	08:22	1.209.411.138	2.409.689	+8,03	g5g6
 24/42+	08:22	1.211.184.000	2.410.292	+M21	Qh5h8+
 24/42	08:22	1.211.184.817	2.410.294	+M21	Qh5h8+ Qf7g8 g5g6 Bc5xe3 Qh8h6+ Be3xh6 Bc1xh6+ Qg8g7 Bh6xg7+ Kf8g8 b3xa4 Bb2c1 f6f7+ Kg8xg7 f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 Rb4b2+ Kg2f3
[...]
 51/42	14:09	2.167.086.836	2.550.101	+M21	Qh5h8+ Qf7g8 g5g6 Bc5xe3 Qh8h6+ Be3xh6 Bc1xh6+ Qg8g7 Bh6xg7+ Kf8g8 b3xa4 Bb2c1 f6f7+ Kg8xg7 f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 Rb4b2+ Kg2f3 Kg7h6 Qe8f8+ Kh6g5 Qf8xf4+ Kg5h5 Bh3g4+ Kh5xg6 Qf4xd6+ Kg6f7 Qd6d7+ Kf7f8 Bg4e6 d5xe4+ Kf3g3 Rb2f2 Kg3xf2 e4e3+ Kf2g3 c3c2 Qd7f7+
 52/78	17:02	2.623.608.108	2.566.296	+M20	Qh5h8+ Qf7g8 g5g6 Bc5xe3 Qh8h6+ Be3xh6 Bc1xh6+ Qg8g7 Bh6xg7+ Kf8g8 b3xa4 Bb2c1 f6f7+ Kg8xg7 f7xe8Q Qa2xh2+ Kg3xh2 Bc1f4+ Kh2g2 Rb4b2+ Kg2f3 Kg7h6 Qe8f8+ Kh6g5 Qf8e7+ Kg5h5 Bh3g4+ Kh5h6 g6g7 d5xe4+ Kf3xe4 Nb1d2+ Ke4xf4 Nd2e4 g7g8N+ Kh6g6 Bg4f5+ Kg6h5 Qe7h7+
Regards from Spain.

Ajedrecista.
LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks.

Post by LevyRook »

Hello, Ajedrecista. Thank you very much!

So, I see that the last 20 moves are verified. In addition to that, Lichess' Stockfish doesn't notice a shorter win earlier (with 70MB it doesn't refuse to analyze the starting position).
LevyRook
Posts: 9
Joined: Sun Apr 14, 2024 7:50 am
Full name: Jim Wood

Re: Research idea: the longest middlegame attacks

Post by LevyRook »

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

Nr3n2/n5Nk/r1p2Q2/r1pp4/BP1P4/rrN1P3/Bbr2PP1/qb3bK1 w - - 1 9

Could someone help me to evaluate this position and find the most resilient defense for Black?

My own conclusions are that Black A) loses material advantage before the 30th move or B) loses material advantage at the 37th move and gets checkmated at the 40th move.