Some "bright" positions

[Jouni]

Here are examples of positions, where bright excels in my P4 2400 PC.

Analysis by bright-0.2c:

[d]r1bqr1k1/5p2/p2p1npb/1p1Pp2p/4P1P1/1PP1NPP1/2BBQ1K1/5R1R w - -

1.Nf5 Bxd2 2.Qxd2 gxf5 3.Qh6 f4 4.g5 Ng4 5.fxg4 Bxg4 6.gxf4 Rc8 7.g6 fxg6 8.fxe5 Rxc3 9.Qxg6+ Kh8 10.Qh6+ Kg8
± (0.84) Depth: 13/44 00:01:06 37317kN
1.Nf5 Bxd2 2.Qxd2 gxf5 3.Qh6 f4 4.g5 Ng4 5.fxg4 Bxg4 6.gxf4 Qc7 7.g6 fxg6 8.fxe5 Rxe5 9.Qxg6+ Kh8 10.Qh6+ Kg8
± (1.05) Depth: 14/46 00:01:24 47313kN

[d]r2qr1k1/pp1nbppp/3p1n2/2pP2N1/2B2B2/3P4/PPP1Q1PP/4RRK1 w - -

1.Nxf7 Kxf7 2.Qe6+ Kf8 3.g4 Qb6 4.g5 Qxb2 5.gxf6 Nxf6 6.Rb1 Qd4+ 7.Be3 Qc3 8.Rxb7 Rab8 9.Rxa7 Qxc2
± (0.82) Depth: 14/53 00:01:41 65697kN
1.Nxf7 Kxf7 2.Qe6+ Kf8 3.g4 Qb6 4.g5 Qxb2 5.gxf6 Nxf6 6.Rb1 Qxc2 7.Rxb7 Rab8 8.Rxb8 Rxb8 9.Bxd6 Re8
± (1.21) Depth: 15/53 00:01:58 77177kN

[d]2kr3r/pp3p1p/2n1b3/q3p3/2p5/b1P1P1N1/P1QN1PPP/1R2KB1R b K -

1...Rxd2 2.Kxd2 Rd8+ 3.Ke1 Nb4 4.cxb4 Bxb4+ 5.Rxb4 Qxb4+ 6.Ke2 c3 7.Ne4 Qb2 8.Qxb2 cxb2 9.Nc3 Bc4+ 10.Kf3 Rd1 11.Bxc4 Rxh1 12.Bd3 Rxh2
³ (-0.56) Depth: 14/50 00:02:35 101mN
1...Rxd2 2.Kxd2 Rd8+ 3.Ke1 Nb4 4.cxb4 Bxb4+ 5.Rxb4 Qxb4+ 6.Ke2 c3 7.Ne4 Qb2 8.Qxb2 cxb2 9.Nc3 Bc4+ 10.Kf3 Rd1 11.Bxc4 Rxh1 12.Bd3 Rxh2
³ (-0.56) Depth: 15/56 00:03:08 122mN

[d]8/B1p2p1P/8/4p3/8/k7/p2K4/8 w - -

1.Bd4 exd4 2.h8Q a1N 3.Kd3 Nb3 4.Kc4 Na5+ 5.Kxd4 c6 6.Qf8+ Ka4 7.Qxf7 Nb3+ 8.Kc3 Na5 9.Qa2+ Kb5 10.Qb2+ Ka6 11.Kd4
+- (6.58) Depth: 15/44 00:00:11 9791kN
1.Bd4 exd4 2.h8Q a1N 3.Kd3 Nb3 4.Kc4 Na5+ 5.Kxd4 c6 6.Qf8+ Ka4 7.Qxf7 Kb4 8.Qe7+ Ka4 9.Kc5 Kb3 10.Qe6+ Ka3
+- (6.63) Depth: 16/44 00:00:12 10684kN

[d]8/8/2N4p/p5kP/P1K5/1P6/8/4b3 w - -

1.Nxa5 Bxa5 2.b4 Bb6 3.a5 Bg1 4.b5 Kf6 5.b6 Ke6 6.Kb5 Kd7 7.a6 Kc8 8.Kc6 Bxb6 9.Kxb6 Kb8 10.Kc5
+- (2.65) Depth: 18/32 00:00:07 8312kN
1.Nxa5 Bxa5 2.b4 Bb6 3.a5 Bg1 4.b5 Kf6 5.b6 Ke6 6.Kb5 Kd7 7.a6 Kc8 8.b7+ Kb8 9.Kc4 Be3 10.Kd5 Bf4 11.Kc5
+- (2.57) Depth: 19/32 00:00:08 9012kN

[d]r3B3/p7/5pp1/4p1B1/8/R6K/p1p1p2p/3k3r w - -

1.Rd3+ Ke1 2.Bh4+ Kf1 3.Rf3+ Kg1 4.Bf2+ Kf1 5.Bc5+ Ke1 6.Bb4+ Kd1 7.Rd3+ Kc1 8.Ba3+ Kb1 9.Rb3+ Ka1 10.Bb2+ Kb1 11.Bxe5+ Kc1 12.Bf4+ Kd1 13.Rd3+ Ke1 14.Bg3+ Kf1 15.Rf3+ Kg1 16.Bf2+ Kf1
+- (#45) Depth: 5/105 00:00:00

Of course there is also black-out positions, but generally bright is great in test suites.

Jouni

[Allard Siemelink]

Here are examples of positions, where bright excels in my P4 2400 PC.
[d]r3B3/p7/5pp1/4p1B1/8/R6K/p1p1p2p/3k3r w - -

1.Rd3+ Ke1 2.Bh4+ Kf1 3.Rf3+ Kg1 4.Bf2+ Kf1 5.Bc5+ Ke1 6.Bb4+ Kd1 7.Rd3+ Kc1 8.Ba3+ Kb1 9.Rb3+ Ka1 10.Bb2+ Kb1 11.Bxe5+ Kc1 12.Bf4+ Kd1 13.Rd3+ Ke1 14.Bg3+ Kf1 15.Rf3+ Kg1 16.Bf2+ Kf1
+- (#45) Depth: 5/105 00:00:00

Of course there is also black-out positions, but generally bright is great in test suites.

Jouni

Cute mate in 45!
I guess any other engine with check and single move extensions would solve it quickly too, of course.
btw, it seems that your gui has a bug, since only the first 16 moves are shown?

If you have saved some of those black-out positions, I would have an interest in these positions too (especially if they should be easy).

[Uri Blass]

Here are examples of positions, where bright excels in my P4 2400 PC.
[d]r3B3/p7/5pp1/4p1B1/8/R6K/p1p1p2p/3k3r w - -

1.Rd3+ Ke1 2.Bh4+ Kf1 3.Rf3+ Kg1 4.Bf2+ Kf1 5.Bc5+ Ke1 6.Bb4+ Kd1 7.Rd3+ Kc1 8.Ba3+ Kb1 9.Rb3+ Ka1 10.Bb2+ Kb1 11.Bxe5+ Kc1 12.Bf4+ Kd1 13.Rd3+ Ke1 14.Bg3+ Kf1 15.Rf3+ Kg1 16.Bf2+ Kf1
+- (#45) Depth: 5/105 00:00:00

Of course there is also black-out positions, but generally bright is great in test suites.

Jouni

Cute mate in 45!
I guess any other engine with check and single move extensions would solve it quickly too, of course.
btw, it seems that your gui has a bug, since only the first 16 moves are shown?

If you have saved some of those black-out positions, I would have an interest in these positions too (especially if they should be easy).

I disgree that every engine with check and single reply extensions would solve it quickly because engine that extend full ply for checks and half ply for single replies may need long time to solve it.

Movei extends more than it but not full ply for single extensions and movei needs clearly bigger depth than bright.

Uri

[Jouni]

Here's another position where bright gives wrong mate (this seldom happens):

[d]8/K6P/5p2/4p1B1/8/7R/p1pRp1p1/2k4b w - -

Analysis by bright-0.2c:

1.Rd1+ Kxd1 2.Rd3+ Ke1 3.Bh4+ Kf1 4.Rf3+ Kg1 5.Bf2+ Kf1 6.Bc5+ Ke1 7.Bb4+ Kd1 8.Rd3+ Kc1 9.Ba3+ Kb1 10.Rb3+ Ka1 11.Bb2+ Kb1 12.Bxe5+ Kc1 13.Bf4+ Kd1 14.Rd3+ Ke1 15.Bg3+ Kf1 16.Rf3+ Kg1
+- (#31) Depth: 9/88 00:00:05 4886kN

This is mate in 34.

Jouni

[Alessandro Scotti]

Here's another position where bright gives wrong mate (this seldom happens):

...

This is mate in 34.

Is this mate proven? Hamsters finds mate in 34 but in some configurations it improves to mate in 30. Someone with Chest?!?

[George Tsavdaris]

Here's another position where bright gives wrong mate (this seldom happens):

...

This is mate in 34.

Is this mate proven? Hamsters finds mate in 34 but in some configurations it improves to mate in 30. Someone with Chest?!?

Chest says mate in 34:


WinCHEST Ver.3.19f+, 01-Feb-2006
Options = -M256 -Z34 -eL -R3 -K3 -P5 -X16 -0 -5 -SUr
Input file: STDIN
Reading job:
% created by ChestUCI Ver.4.4
W: Ka7 Rd2 Rh3 Bg5 Ph7 (5)
B: Kc1 Bh1 Pa2 Pc2 Pe5 Pe2 Pf6 Pg2 (8)
FEN: 8/K6P/5p2/4p1B1/8/7R/p1pRp1p1/2k4b w - -
analysing (special-mate in 34 moves):
Solution (in 34 moves):
d2d1
Time (virt) = 0.359 sec

PV= d2d1 c1d1 h3d3 d1e1 g5h4 e1f1 d3f3 f1g1 h4f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1 a3b2 a1b1 b2e5 b1c1 e5f4 c1d1 b3d3 d1e1 f4g3 e1f1 d3f3 f1g1 g3f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1 a3b2 a1b1 b2f6 b1c1 f6g5 c1d1 b3d3 d1e1 g5h4 e1f1 d3f3 f1g1 h4f2 g1f1 f2g3 f1g1 h7h8q a2a1q h8a1 c2c1q a1c1 e2e1q c1e1
d2d1 c1d1 h3d3 d1e1 g5h4 e1f1 d3f3 f1g1 h4f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1 a3b2 a1b1 b2e5 b1c1 e5f4 c1d1 b3d3 d1e1 f4g3 e1f1 d3f3 f1g1 g3f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1 a3b2 a1b1 b2f6 b1c1 f6g5 c1d1 b3d3 d1e1 g5h4 e1f1 d3f3 f1g1 h4f2 g1f1 f2g3 f1g1 h7h8q a2a1q h8a1 c2c1b a1c1 e2e1b c1e1

[Alessandro Scotti]

Is this mate proven? Hamsters finds mate in 34 but in some configurations it improves to mate in 30. Someone with Chest?!?

Chest says mate in 34:

Drats!

[Alessandro Scotti]

After playing:

Code: Select all

d2d1 c1d1 h3d3 d1e1 g5h4 e1f1 d3f3 f1g1 h4f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1 a3b2 a1b1 b2e5 b1c1 e5f4 c1d1 b3d3 d1e1 f4g3 e1f1 d3f3 f1g1 g3f2 g1f1 f2c5 f1e1 c5b4 e1d1 f3d3 d1c1 b4a3 c1b1 d3b3 b1a1

we reach the position where the PV diverges:

[d]8/K6P/5p2/8/8/BR6/p1p1p1p1/k6b w - - 21 1

Here Chest continues with Bb2+ which Hamsters sees as +M12 but then Hamsters thinks h8=Q is +M8 with the following PV:

Code: Select all

h8=Q g1=Q+ Ka6 Bb7+ Rxb7 Qf1 Bb2+ Kb1 Bxf6+ Kc1 Bb2+ Kd1 Qd4+ Ke1 Bc3+

I have only Shredder 11 to check now and it falls for +M8 too, so I can't see the refutation... what does your engine say?

[Allard Siemelink]

Here Chest continues with Bb2+ which Hamsters sees as +M12 but then Hamsters thinks h8=Q is +M8 with the following PV:

Code: Select all

h8=Q g1=Q+ Ka6 Bb7+ Rxb7 Qf1 Bb2+ Kb1 Bxf6+ Kc1 Bb2+ Kd1 Qd4+ Ke1 Bc3+

At ply 7, bright sees a (different) mate in 8 too:
h7h8=Q g2g1=Q+ Ka7a6 Bh1b7+ Rb3xb7 Qg1g5 Ba3b2+ Ka1b1 Bb2c3+ Kb1c1 Qh8h1+ Qg5g1 Qh1xg1+ e2e1=N Qg1xe1+

I guess it's 'only' a mate in 30 after all and neither Hamsters nor Bright have a bug here.

[Roman Hartmann]

That behaviour seems not uncommon. Roce sees a Mate in 13 first, then a mate in 12 and at ply 8 it will find a mate in 8:

Code: Select all

roce: setboard 8/K6P/5p2/8/8/BR6/p1p1p1p1/k6b w - - 0 1

roce: analyze

 D.   Time    Score  Best line
  1   0.02    2.24   Ba3-b2+
  2   0.07    +M013   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-c5+ kf1-e1 Bc5-b4+ ke1-d1 Rf3-d3+ kd1-c1 Bb4-a3+
                     kc1-b1 Rd3-b3+ kb1-a1 h7-h8=B#
  3   0.15    +M013   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-c5+ kf1-e1 Bc5-b4+ ke1-d1 Rf3-d3+ kd1-c1 Bb4-a3+
                     kc1-b1 Rd3-b3+ kb1-a1 h7-h8=B#
  4   0.41    +M013   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-c5+ kf1-e1 Bc5-b4+ ke1-d1 Rf3-d3+ kd1-c1 Bb4-a3+
                     kc1-b1 Rd3-b3+ kb1-a1 h7-h8=B#
  5   2.09    +M013   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-c5+ kf1-e1 Bc5-b4+ ke1-d1 Rf3-d3+ kd1-c1 Bb4-a3+
                     kc1-b1 Rd3-b3+ kb1-a1 h7-h8=Q#
  6   9.37    +M012   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-g3+ kf1-g1 h7-h8=Q a2-a1=r+ Qh8xa1+ c2-c1=b Qa1xc1+
                     e2-e1=n Qc1xe1#
  7  45.02    +M012   Ba3-b2+ ka1-b1 Bb2xf6+ kb1-c1 Bf6-g5+ kc1-d1 Rb3-d3+
                     kd1-e1 Bg5-h4+ ke1-f1 Rd3-f3+ kf1-g1 Bh4-f2+ kg1-f1
                     Bf2-g3+ kf1-g1 h7-h8=Q a2-a1=r+ Qh8xa1+ c2-c1=b Qa1xc1+
                     e2-e1=n Qc1xe1#
  8   1:42    +M08   h7-h8=Q g2-g1=Q+ Ka7-a6 bh1-b7+ Rb3xb7 qg1-f2 Ba3-b2+
                     ka1-b1 Bb2-c3+ qf2-b6+ Rb7xb6+ kb1-c1 Qh8-h1+ e2-e1=n
                     Qh1xe1#