Author: Jeremiah Penery
Date: 09:51:26 11/27/00
I see Mogens asked for me to post these positions in another thread, but it's
way down near the bottom. I've been wanting to post these for a while anyway,
since it's been a long time since they've been looked at. I'm interested to see
the results from new programs, especially 'speculative' programs like GT, since
these are mostly king-attack positions.
Anyway, here's the original positions, analysis, results from DT-2, and some
other stuff. I've tried to clean it up some, because there were some minor
errors. In #11, I've also inserted what I think is a new winning line for white
in what otherwise would be a drawing line.
One last thing: I don't consider any of these positions truly solved unless the
correct line is found, or a score is found to show that the program understands
the position. Like in #1, it's not solved just by picking Nxh6, but by choosing
the line Nxh6 c3 Nf5!! cxb2 Qg4, which is crushing for white.
--------
Sometime ago, the following 11 positions collected by Pierre Nolot were
posted to rec.games.chess. Pierre claimed that no computers can solve any of
them in reasonable time (and no micros in even a few weeks). A long while back,
he might be right. At this point, a few of them are solvable even under
tournament time control. The ones that we tried overnight are all solvable
in a few hours. DT-2 was searching around 3 million nodes/sec during the
runs. The time probably would be reduced by 5-30 times for the harder
problems if the machine has a better quiescence search.
Position #1
r3qb1k/1b4p1/p2pr2p/3n4/Pnp1N1N1/6RP/1B3PP1/1B1QR1K1 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | | | *Q| *B| | *K|
+---+---+---+---+---+---+---+---+
7 | | *B| | | | | *P| |
+---+---+---+---+---+---+---+---+
6 | *P| | | *P| *R| | | *P|
+---+---+---+---+---+---+---+---+
5 | | | | *N| | | | |
+---+---+---+---+---+---+---+---+
4 | P | *N| *P| | N | | N | |
+---+---+---+---+---+---+---+---+
3 | | | | | | | R | P |
+---+---+---+---+---+---+---+---+
2 | | B | | | | P | P | |
+---+---+---+---+---+---+---+---+
1 | | B | | Q | R | | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Kasparov-Karpov, 20th game 1990
26. Nxh6!! c3
26. ...Rxh6!? 27. Nxd6 Qh5 28. Rg5! Qxd1 29. Nf7+ Kg8 30. Nxh6+
Kh8 31. Rxd1 c3 32. Nf7+ Kg8 33. Bg6! Nf4 34. Bxc3 Nxg6 35. Bxb4
Kxf7 36. Rd7+ Kf6 37. Rxg6+ Kxg6 38. Rxb7 +-
27. Nf5! cxb2 28. Qg4 Bc8
28... g6!? 29. Kh2! Qd7 30. Nh4 Bc6 31. Nc5! dxc5 32. Rxe6 Nf6
33. Nxg6+ Kg7 34. Qg5 Nbd5 35. Ne5 Kh8 36. Nxd7 +-
29. Qh4+ Rh6 30. Nxh6 gxh6 31. Kh2! Qe5 32. Ng5 Qf6 33. Re8 Bf5 34. Qxh6
34. Nf7+ Qxf7 35. Qxh6+ Bh7 36. Rxa8 Nf6 37. Rxf8 Qxf8 38. Qxf8+
Ng8 39. Qg7#
34. ...Qxh6 35. Nf7+ Kh7 36. Bxf5+ Qg6 37. Bxg6+ Kg7 38. Rxa8 Be7 39. Rb8
a5 40. Be4+ Kxf7 41. Bxd5+ +-
Kasparov played Nxh6 here. DT-2 agreed with Kasparov's analysis after
going down the line given in Informant, but could not find the move
on its own in one hour time. When letting it run overnight, it produced
Nxh6 after 8 hours (but would play it with a 6 hours/move time control; that
is, it got first indication that the combination might work after about 6
hours), with the variation 1. Nxh6! c3 2. Nf5 cxb2 3. Qg4 which wins for
white.
Position #2
r4rk1/pp1n1p1p/1nqP2p1/2b1P1B1/4NQ2/1B3P2/PP2K2P/2R5 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | | | | *R| *K| |
+---+---+---+---+---+---+---+---+
7 | *P| *P| | *N| | *P| | *P|
+---+---+---+---+---+---+---+---+
6 | | *N| *Q| P | | | *P| |
+---+---+---+---+---+---+---+---+
5 | | | *B| | P | | B | |
+---+---+---+---+---+---+---+---+
4 | | | | | N | Q | | |
+---+---+---+---+---+---+---+---+
3 | | B | | | | P | | |
+---+---+---+---+---+---+---+---+
2 | P | P | | | K | | | P |
+---+---+---+---+---+---+---+---+
1 | | | R | | | | | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Bronstein - Ljubojevic, Petropolis itz 1973
22. Rxc5!! Nxc5 23. Nf6+ Kh8 24. Qh4 Qb5+ 25. Ke3! h5 26. Nxh5 Qxb3+ +-
26 ...Nd5+ 27. Bxd5 Qd3 28. Kf2 Ne4+ 29. Bxe4 Qd4+ 30. Kg2
Qxb2+ 31. Kh3 +-
Solution is 1. Rxc5! Nxc5 2. Nf6+ Kh8 3. Qh4. Solved under tournament
time control (3 minutes/move, plus extra time if the value for the move
is unstable). Plays it after 2 minutes. Actually spent 4.5 minutes before
the value stabilized to about a piece up.
Position #3
r2qk2r/ppp1b1pp/2n1p3/3pP1n1/3P2b1/2PB1NN1/PP4PP/R1BQK2R w KQkq -
+---+---+---+---+---+---+---+---+
8 | *R| | | *Q| *K| | | *R|
+---+---+---+---+---+---+---+---+
7 | *P| *P| *P| | *B| | *P| *P|
+---+---+---+---+---+---+---+---+
6 | | | *N| | *P| | | |
+---+---+---+---+---+---+---+---+
5 | | | | *P| P | | *N| |
+---+---+---+---+---+---+---+---+
4 | | | | P | | | *B| |
+---+---+---+---+---+---+---+---+
3 | | | P | B | | N | N | |
+---+---+---+---+---+---+---+---+
2 | P | P | | | | | P | P |
+---+---+---+---+---+---+---+---+
1 | R | | B | Q | K | | | R |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Smaguine - Sahovic, Bienne 1990
12. Nxg5!! Bxd1 13. Nxe6 Qb8 14. Nxg7!! Kf8 15. Bh6! Bg4 16. 0-0+
17. Kg8 17. Rf4 +-
Solution move is 1. Nxg5!. Verified that the move is sound by following
the published analysis, but could not play it within one hour time. This
is more a positional sac than what would be normally called tactics.
We took a closer look at this position. 12. Nxg5 is a sound positional
sac, but depending on the temperament of the player, it might not be
the best move. The published annotation gives 12. Bxg5 Bxg5 13. O-O as
+=, but white could play 13. h3 instead and white appears to have a simple
positional squeeze. The critical line in the 12. Nxg5 variation turns out
to be 12. Nxg5 Bxd1 13. Nxe6 Qb8 14. Nxg7 Kd8 15. Kxd1. Black's queen and rooks
are temporarily out of play, black is up a pawn, but white has a protected
passed pawn, and lots of pressure. (The annotator gave one line that
ended "with the attack":). From DT-2's point of view, The Bxg5 line was
gaining 0.20 pawn after each iteration, and so was the Nxg5 line. Except
that the Bxg5 line has about a 0.20 pawn lead at the same depth. There
appears to be no kill in the Nxg5 line when black king goes to d8
instead of the f file. Black would have to give up the extra pawn to
activate the queen and the rooks, and while white is definitely better, black
is not without counter play. On the deepest search that we checked out,
black's evaluation stopped dropping at around -1.4 pawns, and black's pieces
were becoming active.
Position #4
r1b1kb1r/1p1n1ppp/p2ppn2/6BB/2qNP3/2N5/PPP2PPP/R2Q1RK1 w kq -
+---+---+---+---+---+---+---+---+
8 | *R| | *B| | *K| *B| | *R|
+---+---+---+---+---+---+---+---+
7 | | *P| | *N| | *P| *P| *P|
+---+---+---+---+---+---+---+---+
6 | *P| | | *P| *P| *N| | |
+---+---+---+---+---+---+---+---+
5 | | | | | | | B | B |
+---+---+---+---+---+---+---+---+
4 | | | *Q| N | P | | | |
+---+---+---+---+---+---+---+---+
3 | | | N | | | | | |
+---+---+---+---+---+---+---+---+
2 | P | P | P | | | P | P | P |
+---+---+---+---+---+---+---+---+
1 | R | | | Q | | R | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Bronstein - Kotov, candiates, Budapest 1950
10. Nxe6!! Qxe6 11. Nd5 Kd8 12. Bg4 Qe5 13. f4 Qxe4
13. ...Qxb2 14. Bxd7 Bxd7 15. Rb1 Qa3 16. Nxf6 Bb5 17. Qd4 Qc5
18. Rfd1 +-
14. Bxd7 Bxd7 15. Nxf6 gxf6 16. Bxf6+ Kc7 17. Bxh8 +-
Solution: 1. Nxe6 Qxe6 2. Nd5 Kd8 3. Bg4. Plays it after 3.8 hours, would play
it under 2.5 hour/move time control.
Position #5
r2qrb1k/1p1b2p1/p2ppn1p/8/3NP3/1BN5/PPP3QP/1K3RR1 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | | *Q| *R| *B| | *K|
+---+---+---+---+---+---+---+---+
7 | | *P| | *B| | | *P| |
+---+---+---+---+---+---+---+---+
6 | *P| | | *P| *P| *N| | *P|
+---+---+---+---+---+---+---+---+
5 | | | | | | | | |
+---+---+---+---+---+---+---+---+
4 | | | | N | P | | | |
+---+---+---+---+---+---+---+---+
3 | | B | N | | | | | |
+---+---+---+---+---+---+---+---+
2 | P | P | P | | | | Q | P |
+---+---+---+---+---+---+---+---+
1 | | K | | | | R | R | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Spassky - Petrossian, w ch (19), Moscow 1969
21. e5!! dxe5 22. Ne4! Nh5 23. Qg6!?
23. Qg4!! Nf4 24. Nf3 Qc7 25. Nh4 +-
23. ...exd4? 24. Ng5 +-
Took 4 hours to find e5!. 1. e5! dxe5 2. Ne4 Nh5 3. Qg6. More than a
piece up. The minimum time control needed to play it is around 2 hours/move.
Position #6
rnbqk2r/1p3ppp/p7/1NpPp3/QPP1P1n1/P4N2/4KbPP/R1B2B1R b kq -
+---+---+---+---+---+---+---+---+
8 | *R| *N| *B| *Q| *K| | | *R|
+---+---+---+---+---+---+---+---+
7 | | *P| | | | *P| *P| *P|
+---+---+---+---+---+---+---+---+
6 | *P| | | | | | | |
+---+---+---+---+---+---+---+---+
5 | | N | *P| P | *P| | | |
+---+---+---+---+---+---+---+---+
4 | Q | P | P | | P | | *N| |
+---+---+---+---+---+---+---+---+
3 | P | | | | | N | | |
+---+---+---+---+---+---+---+---+
2 | | | | | K | *B| P | P |
+---+---+---+---+---+---+---+---+
1 | R | | B | | | B | | R |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Malaniouk - Ivantchouk, Moscow 1988
13. ...axb5!! 14. Qxa8 Bd4 15. Nxd4 cxd4 16. Qxb8 0-0! 17. Ke1 Qh4
18. g3 Qf6 19. Bf4 g5?
19. ...Bf5!!
19. ...d3! 20. Rc1 exf4 21. Qxf4 Qd4 22. Rd1 bxc4 23. e5 Qc3+
24. Rd2 Re8 25. Bxd3 cxd3 -+
First, 19. ...Bf5 was played instantly (at 6 ply) by both DT-1 and DT-2,
and within 30 seconds, both thought that black is winning big.
An interesting line is instead of playing 17. Ke1 as in the game, playing
17. c5!?. Black's attack looks menacing, but there is no obvious win.
13. ...axb5!! seems clearly the best move in the position, even though
Ivanchuk did not see all the complications over the board, and we cannot
establish that it necessarily wins. It probably would tie down the
machine for a few days to find the move. Perhaps we will try it
sometime later.
Position #7
1r1bk2r/2R2ppp/p3p3/1b2P2q/4QP2/4N3/1B4PP/3R2K1 w k -
+---+---+---+---+---+---+---+---+
8 | | *R| | *B| *K| | | *R|
+---+---+---+---+---+---+---+---+
7 | | | R | | | *P| *P| *P|
+---+---+---+---+---+---+---+---+
6 | *P| | | | *P| | | |
+---+---+---+---+---+---+---+---+
5 | | *B| | | P | | | *Q|
+---+---+---+---+---+---+---+---+
4 | | | | | Q | P | | |
+---+---+---+---+---+---+---+---+
3 | | | | | N | | | |
+---+---+---+---+---+---+---+---+
2 | | B | | | | | P | P |
+---+---+---+---+---+---+---+---+
1 | | | | R | | | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Todorovic - Tosic, Arandjelovac, 1993.
1.Rxd8+!! Rxd8
1...Kxd8 2.Ra7! Qe2 3.Qd4+ Ke8 4.h3 Qe1+
5.Kh2 Rd8 6.Qc5 Qh4 7.Ba3 Rd7 8.Ra8+ Rd8 9.g3 1-0
2.Ba3 Qe2 3.h3! Bd7
3...Qe1+ 4.Kh2 Qa5 5.Re7+ Kf8 6.Rd7+ Kg8 7.Bb4 Rxd7 8.Bxa5 +-
4.Nf5! Qd1+ 5.Kh2 f6 6.e5xf6 1-0
This one we left the machine ran overnight. It found that 1. Rxd8! wins.
1. Rxd8! Kxd8 2. Ra7 and if 2. ...Qe2 3. Qd4 Ke8 4. h3. Took 12 hours
to get the value back, but would have played it if the time control
is 6 hours/move.
Position #8
r3rbk1/ppq2ppp/2b1pB2/8/6Q1/1P1B3P/P1P2PP1/R2R2K1 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | | | *R| *B| *K| |
+---+---+---+---+---+---+---+---+
7 | *P| *P| *Q| | | *P| *P| *P|
+---+---+---+---+---+---+---+---+
6 | | | *B| | *P| B | | |
+---+---+---+---+---+---+---+---+
5 | | | | | | | | |
+---+---+---+---+---+---+---+---+
4 | | | | | | | Q | |
+---+---+---+---+---+---+---+---+
3 | | P | | B | | | | P |
+---+---+---+---+---+---+---+---+
2 | P | | P | | | P | P | |
+---+---+---+---+---+---+---+---+
1 | R | | | R | | | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Goufeld - Osnos, Koutaissi 1978
24. Bxh7+!! Kxh7 25. Qh5+ Kg8 26. Rd4! gxf6 27. Rg4+ Bg7
28. Qh6 Kf8 29. Rxg7! Rac8
29. ...Be4 30. Rg4+ Ke7 31. Rxe4 Rad8 32. c4 Qa5 33. Rae1 +-
30. Qh7 b5 31. Rd1 Bd5 32. c4 bxc4 33. bxc4
As Deep Thought found out, 26 ... gxf6 seems to be a mistake.
More on that later, but this one is dubious now!
The move played was 1. Bxh7, but as it turns out 1. Bxh7 might not be the
best move. Osnos defended poorly and got slaughtered. With best black
defence, white only maintains a positional edge after 1. Bxh7 Kxh7 2. Qh5+
Kg8 3. Rd4 Bf3! (with the idea of Qxc2, and then Q to king side to defend
the king). DT-2 prefers to play c4, which threatens Bxh7 for real.
Position #9
r4r1k/4bppb/2n1p2p/p1n1P3/1p1p1BNP/3P1NP1/qP2QPB1/2RR2K1 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | | | | *R| | *K|
+---+---+---+---+---+---+---+---+
7 | | | | | *B| *P| *P| *B|
+---+---+---+---+---+---+---+---+
6 | | | *N| | *P| | | *P|
+---+---+---+---+---+---+---+---+
5 | *P| | *N| | P | | | |
+---+---+---+---+---+---+---+---+
4 | | *P| | *P| | B | N | P |
+---+---+---+---+---+---+---+---+
3 | | | | P | | N | P | |
+---+---+---+---+---+---+---+---+
2 | *Q| P | | | Q | P | B | |
+---+---+---+---+---+---+---+---+
1 | | | R | R | | | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Weinstein - Elyoseph, Israel 1992
1. Ng5!! hxg5 2. hxg5! Rac8 3. Nf6!! Nb8
3. ...gxf6 4. gxf6 Rfe8 5. Qh5 Rg8 6. Rxc5! Bg6! 7. Qh4 Bxc5
8. Be4 Ne7 9. Kg2 Qd5 10. Bxd5 +-
4. Qh5 Bxf6 5. gxf6 gxf6 6. Rxc5 Rxc5 7. Be4 f5 8. Kg2 Rg8 9. Rh1 Rg7
10. Bh6 Nd7 11. Bxg7+ Kxg7 12. Qxh7+
After 9 minutes, it played 1. Nf6, expecting 1. ...Rfc8 2. Nxh7 Kxh7 3. Ra1.
The score was slightly nagative for white. On longer searches, it went up
to half a pawn and creeping up.
Position #10
r1b2rk1/1p1nbppp/pq1p4/3B4/P2NP3/2N1p3/1PP3PP/R2Q1R1K w - -
+---+---+---+---+---+---+---+---+
8 | *R| | *B| | | *R| *K| |
+---+---+---+---+---+---+---+---+
7 | | *P| | *N| *B| *P| *P| *P|
+---+---+---+---+---+---+---+---+
6 | *P| *Q| | *P| | | | |
+---+---+---+---+---+---+---+---+
5 | | | | B | | | | |
+---+---+---+---+---+---+---+---+
4 | P | | | N | P | | | |
+---+---+---+---+---+---+---+---+
3 | | | N | | *P| | | |
+---+---+---+---+---+---+---+---+
2 | | P | P | | | | P | P |
+---+---+---+---+---+---+---+---+
1 | R | | | Q | | R | | K |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Van der Wiel - Ribli Amsterdam 1980.
15. Rxf7!! Rxf7 16. Bxf7+ Kxf7 17. Qh5+ Kg8 18. Qe8+ Bf8
19. Nd5 Qxd4 20. Nxe7+ Kh8 21. Rf1 Qf6 22. Rxf6
Solution is 1. Rxf7 Rxf7 2. Bxf7+ Kxf7 3. Qh5+. Plays it in less than 2
minutes, score stablized within 5 minutes to a pawn plus.
Position #11
r1b3k1/p2p1nP1/2pqr1Rp/1p2p2P/2B1PnQ1/1P6/P1PP4/1K4R1 w - -
+---+---+---+---+---+---+---+---+
8 | *R| | *B| | | | *K| |
+---+---+---+---+---+---+---+---+
7 | *P| | | *P| | *N| P | |
+---+---+---+---+---+---+---+---+
6 | | | *P| *Q| *R| | R | *P|
+---+---+---+---+---+---+---+---+
5 | | *P| | | *P| | | P |
+---+---+---+---+---+---+---+---+
4 | | | B | | P | *N| Q | |
+---+---+---+---+---+---+---+---+
3 | | P | | | | | | |
+---+---+---+---+---+---+---+---+
2 | P | | P | P | | | | |
+---+---+---+---+---+---+---+---+
1 | | K | | | | | R | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
Teichmann - NN, Zurich 1920
1. Rxh6!! Nxh6
1. ...Rxh6 2. Bxf7+ Rxf7 3. g8=Q+
2. Qg5 Nf7 3. Qd8+!! Nxd8 4. h6 Qd4!! 5. h7+ Kf7 6. g8=Q+ Ke7 7. h8=Q Kd6
8. Rg7 Qxd2!! 9. Qxd8 Kc5 10. Rxd7 Bxd7 11. Qxa8 Kb4 12. Qxa7
12. Qh1!! seems to be winning...(JP)
12. ...Qe1 13. Kb2 Qc3 1/2-1/2 as white cannot escape the black checks.
Bxe6 appears somewhat worse for white, but 1. Rh6 Nh6 2. Qg5 Nf7 3. Qd8 appears
to be a repetition draw or slightly ahead for white. Plays 1. Rxh6 after
5 minutes, thought white was slightly ahead, but going down the line, it
appeared that black had enough pressure for a draw.
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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