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Jul 28, 1994, 2:19:37 PM7/28/94

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Sometime ago, the following 11 positions collected by Pierre Nolot were

posted to rgc. 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.

posted to rgc. 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.

The comments below might be considered spoilers. The first line for

each position is in a computer-readable notation.

1 ;r3;q;b1;k/1;b4;p1/;p2;p;r2;p/3;n4/p;n;p1n1n1/6rp/1b3pp1/1b1qr1k1/40

white to move

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

Source: Kasparov-Karpov, Lyon 1990.

Kasparov played Nh6 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

Nh6 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. Nh6! c3 2. Nf5 cb2 3. Qg4 ... which wins for

white.

2 ;r4;r;k1/;p;p1;n1;p1;p/1;n;qP2;p1/2;b1p1b1/4nq2/1b3p2/pp2k2p/2r5/40

White to move

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

Source: Bronstein-Ljubojevic, Petropolis 1973.

Solution is 1. Rc5! Nc5 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.

3 ;r2;q;k2;r/;p;p;p1;b1;p;p/2;n1;p3/3;pp1;n1/3p2;b1/2pb1nn1/pp4pp/r1bqk2r/40

White to move

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

Source: Smagin-Sahovic, Biel 1990.

Solution move is 1. Ng5!. 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.

4 ;r1;b1;k;b1;r/1;p1;n1;p;p;p/;p2;p;p;n2/6bb/2;qnp3/2n5/ppp2ppp/r2q1rk1/40

White to move

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

Source: Keres-Kotov, Budapest 1950.

Solution: 1. Ne6 Qe6 2. Nd5 Kd8 3. Bg4. Plays it after 3.8 hours, would play

it under 2.5 hour/move time control.

5 ;r2;q;r;b1;k/1;p1;b2;p1/;p2;p;p;n1;p/8/3np3/1bn5/ppp3qp/1k3rr1/40

White to move

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

Source: Spassky-Petrosian, Moskow 1969.

Took 4 hours to find e5!. 1. e5! de5 2. Ne4 Nh5 3. Qg6... More than a

piece up. The minimum time control needed to play it is around 2 hours/move.

6 ;r;n;b;q;k2;r/1;p3;p;p;p/;p7/1n;pp;p3/qpp1p1;n1/p4n2/4k;bpp/r1b2b1r/41

Black to move

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

Source: Melaniuk-Ivanchuk, USSR 1988.

Ivanchuk played 1. ... ab5! which appears to be a sound positional sacrifice.

Calling this position a tactical one, however, is a little unfair on Pierre's

part. Ivanchuk, by the way, could not find the best continuations over the

board, but won it anyway due to Melaniuk's inaccurate defence. Could not

solve it in one hour. Probably a home preparation. The same move was

replayed 3 years later in some random tournament.

7 1;r1;b;k2;r/2r2;p;p;p/;p3;p3/1;b2p2;q/4qp2/4n3/1b4pp/3r2k1/40

White to move

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

Source: unknown.

This one we left the machine ran overnight. It found that 1. Rd8! wins.

1. Rd8! Kd8 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.

8 ;r3;r;b;k1/;p;p;q2;p;p;p/2;b1;pb2/8/6q1/1p1b3p/p1p2pp1/r2r2k1/40

White to move

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

Source: Gufeld-Osnos, USSR 1978.

The move played was 1. Bh7, but as it turns out 1. Bh7 might not be the

best move. Osnos defended poorly and got slaughtered. With best black

defence, white only maintains a positional edge after 1. Bh7 Kh7 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 Bh7 for real.

9 ;r4;r1;k/4;b;p;p;b/2;n1;p2;p/;p1;n1p3/1;p1;p1bnp/3p1np1/;qp2qpb1/2rr2k1/40

White to move

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

Source: unknown.

After 9 minutes, it played 1. Nf6, expecting 1. ... Rfc8 2. Nh7 Kh7 3. Ra1 ...

The score was slightly nagative for white. On longer searches, it went up

to half a pawn and creeping up.

10 ;r1;b2;r;k1/1;p1;n;b;p;p;p/;p;q1;p4/3b4/p2np3/2n1;p3/1pp3pp/r2q1r1k/40

White to move

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

Source: Van der Wiel-Ribli, Amsterdam 1980.

Solution is 1. Rf7 Rf7 2. Bf7 Kf7 3. Qh5. Plays it in less than 2 minutes,

score stablized within 5 minutes to a pawn plus.

11 ;r1;b3;k1/;p2;p1;np1/2;p;q;r1r;p/1;p2;p2p/2b1p;nq1/1p6/p1pp4/1k4r1/40

White to move

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

Source: unknown

Be6 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. Rh6 after

5 minutes, thought white was slightly ahead, but going down the line, it

appeared that black had enough pressure for a draw.

Jul 29, 1994, 7:44:00 AM7/29/94

to

f...@watson.ibm.com (Feng-Hsiung Hsu) writes:

>Sometime ago, the following 11 positions collected by Pierre Nolot were

>posted to rgc. 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.

I just phoned Pierre, and he admits he is very impressed by DT-2'sresults!

So am I, and we thank you for the time you have spent on these positions.

I'll post the solutions according to Pierre as given in Gambisco

separately, but first I'll just give you his comments on DT's outstanding

results (much much better than the best micros)

>1 ;r3;q;b1;k/1;b4;p1/;p2;p;r2;p/3;n4/p;n;p1n1n1/6rp/1b3pp1/1b1qr1k1/40

>Source: Kasparov-Karpov, Lyon 1990.

>Kasparov played Nh6 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

>Nh6 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. Nh6! c3 2. Nf5 cb2 3. Qg4 ... which wins for

>white.

Very good. This is not an easy one!

>2 ;r4;r;k1/;p;p1;n1;p1;p/1;n;qP2;p1/2;b1p1b1/4nq2/1b3p2/pp2k2p/2r5/40

>Source: Bronstein-Ljubojevic, Petropolis 1973.

>Solution is 1. Rc5! Nc5 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.

Excellent!! and this is not supposed to be an easy one. Your score proves

you found it for the good reasons.

>3 ;r2;q;k2;r/;p;p;p1;b1;p;p/2;n1;p3/3;pp1;n1/3p2;b1/2pb1nn1/pp4pp/r1bqk2r/40

>Source: Smagin-Sahovic, Biel 1990.

>Solution move is 1. Ng5!. 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.

Well, Pierre still calls it tactics!

>4 ;r1;b1;k;b1;r/1;p1;n1;p;p;p/;p2;p;p;n2/6bb/2;qnp3/2n5/ppp2ppp/r2q1rk1/40

>Source: Keres-Kotov, Budapest 1950.

>Solution: 1. Ne6 Qe6 2. Nd5 Kd8 3. Bg4. Plays it after 3.8 hours, would play

>it under 2.5 hour/move time control.

Very good!

>5 ;r2;q;r;b1;k/1;p1;b2;p1/;p2;p;p;n1;p/8/3np3/1bn5/ppp3qp/1k3rr1/40

>Source: Spassky-Petrosian, Moskow 1969.

>Took 4 hours to find e5!. 1. e5! de5 2. Ne4 Nh5 3. Qg6... More than a

>piece up. The minimum time control needed to play it is around 2 hours/move.

Very good, but 3.Qg4 is even stronger (spassky played Qg6)

Hiarcs also finds this one, and also gives 3Qg6

>6 ;r;n;b;q;k2;r/1;p3;p;p;p/;p7/1n;pp;p3/qpp1p1;n1/p4n2/4k;bpp/r1b2b1r/41

>Source: Melaniuk-Ivanchuk, USSR 1988.

>Ivanchuk played 1. ... ab5! which appears to be a sound positional sacrifice.

>Calling this position a tactical one, however, is a little unfair on Pierre's

>part. Ivanchuk, by the way, could not find the best continuations over the

>board, but won it anyway due to Melaniuk's inaccurate defence. Could not

>solve it in one hour. Probably a home preparation. The same move was

>replayed 3 years later in some random tournament.

All this is perfectly right, except that Pierre still thinks this is tactics.

Very deep tactics.

>7 1;r1;b;k2;r/2r2;p;p;p/;p3;p3/1;b2p2;q/4qp2/4n3/1b4pp/3r2k1/40

>8 - R - B K * - R

Jul 29, 1994, 8:26:29 AM7/29/94

to

In article <31aqbp$5...@sheckley.cnam.fr> m...@cnam.cnam.fr (Marc-Francois Baudot) writes:

>>9 ;r4;r1;k/4;b;p;p;b/2;n1;p2;p/;p1;n1p3/1;p1;p1bnp/3p1np1/;qp2qpb1/2rr2k1/40

>>9 ;r4;r1;k/4;b;p;p;b/2;n1;p2;p/;p1;n1p3/1;p1;p1bnp/3p1np1/;qp2qpb1/2rr2k1/40

>>Source: unknown.

>

>>After 9 minutes, it played 1. Nf6, expecting 1. ... Rfc8 2. Nh7 Kh7 3. Ra1 ...

>>The score was slightly nagative for white. On longer searches, it went up

>>to half a pawn and creeping up.

>

>This is the hardest of them all, and Pierre has not been able to >

>>After 9 minutes, it played 1. Nf6, expecting 1. ... Rfc8 2. Nh7 Kh7 3. Ra1 ...

>>The score was slightly nagative for white. On longer searches, it went up

>>to half a pawn and creeping up.

>

>prove it is correct, so any further analysis is wellcome!

>Proposed move is Ng5 I think, see my post with the solutions

>for more information.

From possibly faulty memory, the Nf6 line traps black queen for a rook and

bishop, winning a pawn in the process. Will check on Ng5, but Nf6 does

appear to be winning. If black refuses to give up the queen, his king

gets caught without pants.

Jul 29, 1994, 7:49:13 AM7/29/94

to

Newsgroups: rec.games.chess

Subject: Re: Nolot's 11 difficult positions (possible spoilers)

References: <CtnxK...@hawnews.watson.ibm.com>

Subject: Re: Nolot's 11 difficult positions (possible spoilers)

References: <CtnxK...@hawnews.watson.ibm.com>

f...@watson.ibm.com (Feng-Hsiung Hsu) writes:

>Sometime ago, the following 11 positions collected by Pierre Nolot were

>posted to rgc. 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.

I just phoned Pierre, and he admits he is very impressed by DT-2'sresults!

So am I, and we thank you for the time you have spent on these positions.

I'll post the solutions according to Pierre as given in Gambisco

separately, but first I'll just give you his comments on DT's outstanding

results (much much better than the best micros)

>1 ;r3;q;b1;k/1;b4;p1/;p2;p;r2;p/3;n4/p;n;p1n1n1/6rp/1b3pp1/1b1qr1k1/40

>Source: Kasparov-Karpov, Lyon 1990.

>Kasparov played Nh6 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

>Nh6 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. Nh6! c3 2. Nf5 cb2 3. Qg4 ... which wins for

>white.

Very good. This is not an easy one!

>2 ;r4;r;k1/;p;p1;n1;p1;p/1;n;qP2;p1/2;b1p1b1/4nq2/1b3p2/pp2k2p/2r5/40

>Source: Bronstein-Ljubojevic, Petropolis 1973.

>Solution is 1. Rc5! Nc5 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.

Excellent!! and this is not supposed to be an easy one. Your score proves

you found it for the good reasons.

>3 ;r2;q;k2;r/;p;p;p1;b1;p;p/2;n1;p3/3;pp1;n1/3p2;b1/2pb1nn1/pp4pp/r1bqk2r/40

>Source: Smagin-Sahovic, Biel 1990.

>Solution move is 1. Ng5!. 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.

Well, Pierre still calls it tactics!

>4 ;r1;b1;k;b1;r/1;p1;n1;p;p;p/;p2;p;p;n2/6bb/2;qnp3/2n5/ppp2ppp/r2q1rk1/40

>Source: Keres-Kotov, Budapest 1950.

>Solution: 1. Ne6 Qe6 2. Nd5 Kd8 3. Bg4. Plays it after 3.8 hours, would play

>it under 2.5 hour/move time control.

Very good!

>5 ;r2;q;r;b1;k/1;p1;b2;p1/;p2;p;p;n1;p/8/3np3/1bn5/ppp3qp/1k3rr1/40

>Source: Spassky-Petrosian, Moskow 1969.

>Took 4 hours to find e5!. 1. e5! de5 2. Ne4 Nh5 3. Qg6... More than a

>piece up. The minimum time control needed to play it is around 2 hours/move.

Very good, but 3.Qg4 is even stronger (spassky played Qg6)

Hiarcs also finds this one, and also gives 3Qg6

>6 ;r;n;b;q;k2;r/1;p3;p;p;p/;p7/1n;pp;p3/qpp1p1;n1/p4n2/4k;bpp/r1b2b1r/41

>Source: Melaniuk-Ivanchuk, USSR 1988.

>Ivanchuk played 1. ... ab5! which appears to be a sound positional sacrifice.

>Calling this position a tactical one, however, is a little unfair on Pierre's

>part. Ivanchuk, by the way, could not find the best continuations over the

>board, but won it anyway due to Melaniuk's inaccurate defence. Could not

>solve it in one hour. Probably a home preparation. The same move was

>replayed 3 years later in some random tournament.

All this is perfectly right, except that Pierre still thinks this is tactics.

Very deep tactics.

>7 1;r1;b;k2;r/2r2;p;p;p/;p3;p3/1;b2p2;q/4qp2/4n3/1b4pp/3r2k1/40

>Source: unknown.

>This one we left the machine ran overnight. It found that 1. Rd8! wins.

>1. Rd8! Kd8 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.

Right!

>8 ;r3;r;b;k1/;p;p;q2;p;p;p/2;b1;pb2/8/6q1/1p1b3p/p1p2pp1/r2r2k1/40

>Source: Gufeld-Osnos, USSR 1978.

>The move played was 1. Bh7, but as it turns out 1. Bh7 might not be the

>best move. Osnos defended poorly and got slaughtered. With best black

>defence, white only maintains a positional edge after 1. Bh7 Kh7 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 Bh7 for real.

Pierre is chacking his analysis right now, and it seems DT is right!

Excellent! (he did not see Bf3!)

>9 ;r4;r1;k/4;b;p;p;b/2;n1;p2;p/;p1;n1p3/1;p1;p1bnp/3p1np1/;qp2qpb1/2rr2k1/40

>Source: unknown.

>After 9 minutes, it played 1. Nf6, expecting 1. ... Rfc8 2. Nh7 Kh7 3. Ra1 ...

>The score was slightly nagative for white. On longer searches, it went up

>to half a pawn and creeping up.

This is the hardest of them all, and Pierre has not been able to

prove it is correct, so any further analysis is wellcome!

Proposed move is Ng5 I think, see my post with the solutions

for more information.

>10 ;r1;b2;r;k1/1;p1;n;b;p;p;p/;p;q1;p4/3b4/p2np3/2n1;p3/1pp3pp/r2q1r1k/40

>Source: Van der Wiel-Ribli, Amsterdam 1980.

>Solution is 1. Rf7 Rf7 2. Bf7 Kf7 3. Qh5. Plays it in less than 2 minutes,

>score stablized within 5 minutes to a pawn plus.

Really excellent. Some programs find this one after a few hours

(Frits 2...) but with an equal score, and then they switch to

another move. DT sees at least a pawn, so it has really found it.

It should go up to about a piece up. Could you give the variations

it saw?

>11 ;r1;b3;k1/;p2;p1;np1/2;p;q;r1r;p/1;p2;p2p/2b1p;nq1/1p6/p1pp4/1k4r1/40

>Source: unknown

>Be6 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. Rh6 after

>5 minutes, thought white was slightly ahead, but going down the line, it

>appeared that black had enough pressure for a draw.

This was the "trap" for the readers of Gambisco.

What you say is the expected solution! Rh6 only draws even though

it is said to be winning in some books!

Well, we are impressed. Pierre would be interested in figures like

number of nodes, depth, and exact variations.

He would also be very much intersted in the results of Hitech and

B* Hitech, Cray Blitz, *Socrates and all the others! (Botvinnik's

program should score well on these positions :-)!)

Thanks a lot!

Marc-Francois Baudot

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