Some Chess960/FRC positions to be confirmed

[SMIRF]

There are five positions critical to Chess960 / FRC to be verified:

Code: Select all

XFEN 00: r1k1r2q/p1ppp1pp/8/8/8/8/P1PPP1PP/R1K1R2Q w KQkq - 0 1
   +-*--b--*--d--*--f--g--h-+
 8 |[r]:::[k]:::[r]:::   [q]|
 7 |[p]   [p][p][p]   [p][p]|
 6 |   :::   :::   :::   :::|
 5 |:::   :::   :::   :::   |
 4 |   :::   :::   :::   :::|
 3 |:::   :::   :::   :::   |
 2 |<P>&#58;&#58;&#58;<P><P><P>&#58;&#58;&#58;<P><P>|
 1 |<R>   <K>   <R>   &#58;&#58;&#58;<Q>|
&#40;w&#41;+-*--b--*--d--*--f--g--h-+

Ply      Moves       &#91;x&#93;   &#91;ep&#93;       &#91;+&#93; &#91;++&#93; Prom     Cstl   Sec
 1&#58;         23         0      0         0    0    0        2  0.00
 2&#58;        522         0      0         4    0    0       43  0.00
 3&#58;      12333        74      0       186    0    0      620  0.00
 4&#58;     285754      2435      0      5623    0    0    13951  0.01
 5&#58;    7096972    114337    127    187447    0    0   223136  0.11
 6&#58;  172843489   3464866   2788   5038016   41    0  5381012  2.78
 7&#58; 4557457200 128157348 178077 159739876 9326    0 99092024 71.01


XFEN 01&#58; r1k2r1q/p1ppp1pp/8/8/8/8/P1PPP1PP/R1K2R1Q w KQkq - 0 1
   +-*--b--*--d--e--*--g--h-+
 8 |&#91;r&#93;&#58;&#58;&#58;&#91;k&#93;&#58;&#58;&#58;   &#91;r&#93;   &#91;q&#93;|
 7 |&#91;p&#93;   &#91;p&#93;&#91;p&#93;&#91;p&#93;   &#91;p&#93;&#91;p&#93;|
 6 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 5 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 4 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 3 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 2 |<P>&#58;&#58;&#58;<P><P><P>&#58;&#58;&#58;<P><P>|
 1 |<R>   <K>   &#58;&#58;&#58;<R>&#58;&#58;&#58;<Q>|
&#40;w&#41;+-*--b--*--d--e--*--g--h-+

Ply       Moves       &#91;x&#93;   &#91;ep&#93;       &#91;+&#93;   &#91;++&#93; Prom      Cstl    Sec
 1&#58;          28         1      0         1      0    0         1   0.00
 2&#58;         738        27      0        21      0    0        30   0.00
 3&#58;       20218       754      0       628      0    0       596   0.00
 4&#58;      541480     20431      0     16130      0    0     16992   0.01
 5&#58;    15194841    611601    155    500165    140    0    350001   0.23
 6&#58;   418430598  17380292   4071  13988947   4692    0   9982101   6.32
 7&#58; 12094237108 546917707 301194 442095597 211521    0 216925840 179.95


XFEN 02&#58; 8/8/8/4B2b/6nN/8/5P2/2R1K2k w Q - 0 1
   +-a--b--c--d--e--f--g--h-+
 8 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 7 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 6 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 5 |&#58;&#58;&#58;   &#58;&#58;&#58;   <B>   &#58;&#58;&#58;&#91;b&#93;|
 4 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;&#91;n&#93;<N>|
 3 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 2 |   &#58;&#58;&#58;   &#58;&#58;&#58;   <P>   &#58;&#58;&#58;|
 1 |&#58;&#58;&#58;   <R>   <K>   &#58;&#58;&#58;&#91;k&#93;|
&#40;w&#41;+-a--b--*--d--*--f--g--h-+

Ply      Moves      &#91;x&#93; &#91;ep&#93;      &#91;+&#93;  &#91;++&#93; Prom    Cstl   Sec
 1&#58;         34        0    0        3     0    0       1  0.00
 2&#58;        318       52    0        8     2    0       0  0.00
 3&#58;       9002      171    0      539     0    0      93  0.00
 4&#58;     118388     8289    0     5952   124    0       0  0.00
 5&#58;    3223406    89276    0   165371    26    0   19739  0.05
 6&#58;   44554839  2732299    0  2089677 33353    0       0  0.79
 7&#58; 1205627532 37587736    0 55094715 37937    0 4020384 19.43


XFEN 03&#58; 2r5/8/8/8/8/8/6PP/k2KR3 w K - 0 1
   +-a--b--c--d--e--f--g--h-+
 8 |   &#58;&#58;&#58;&#91;r&#93;&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 7 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 6 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 5 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 4 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 3 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 2 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;<P><P>|
 1 |&#91;k&#93;   &#58;&#58;&#58;<K><R>   &#58;&#58;&#58;   |
&#40;w&#41;+-a--b--c--*--*--f--g--h-+

Ply      Moves       &#91;x&#93; &#91;ep&#93;       &#91;+&#93; &#91;++&#93; Prom  Cstl   Sec
 1&#58;         17         0    0         3    0    0     1  0.00
 2&#58;        242         1    0        28    0    0     0  0.00
 3&#58;       3931        55    0       390    0    0    52  0.00
 4&#58;      57700      1322    0      5827    0    0     0  0.00
 5&#58;     985298     13562    0     72091    0    0  2121  0.02
 6&#58;   14751778    435453    0   1402904    0    0     0  0.25
 7&#58;  259604208   3731512    0  17710013    0    0 68600  4.78
 8&#58; 3914405614 125072730    0 364180610    0    0     0 66.16


XFEN 04&#58; 4r3/3k4/8/8/8/8/6PP/qR1K1R2 w KQ - 0 1
   +-a--b--c--d--e--f--g--h-+
 8 |   &#58;&#58;&#58;   &#58;&#58;&#58;&#91;r&#93;&#58;&#58;&#58;   &#58;&#58;&#58;|
 7 |&#58;&#58;&#58;   &#58;&#58;&#58;&#91;k&#93;&#58;&#58;&#58;   &#58;&#58;&#58;   |
 6 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 5 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 4 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;|
 3 |&#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;   |
 2 |   &#58;&#58;&#58;   &#58;&#58;&#58;   &#58;&#58;&#58;<P><P>|
 1 |&#91;q&#93;<R>&#58;&#58;&#58;<K>&#58;&#58;&#58;<R>&#58;&#58;&#58;   |
&#40;w&#41;+-a--*--c--*--e--*--g--h-+

Ply      Moves       &#91;x&#93; &#91;ep&#93;       &#91;+&#93; &#91;++&#93; Prom     Cstl    Sec
 1&#58;         19         1    0         1    0    0        0   0.00
 2&#58;        628        20    0        76    0    0        0   0.00
 3&#58;      12858       499    0      1090    0    0      163   0.00
 4&#58;     405636     15223    0     62483    0    0        0   0.01
 5&#58;    8992652    286260    0    857746    0    0    81416   0.15
 6&#58;  281330710  11668588    0  48470016 1034    0        0   4.33
 7&#58; 6447669114 196804371    0 631079536    0    0 35649155 109.29

Thank you for confirmating / refuting results.

(kings and rooks while being unmoved and having castling rights are marked by a '*' instead of column letters)

[mar]

My engine agrees with all your results.

[SMIRF]

Thank you for confirming - those are heavy Chess960 positions.

[mar]

Yes, I remember I had problems with orthogonal opponent slider on back rank preventing FRC castling some time ago (this can't happen in orthodox chess) - position #4.

[Evert]

These are great!

These positions have helped me find a flaw in my makemove that would corrupt the board in FRC positions where the king moves to the rook square (basically, the rook wasn't removed before the king moved there).

With that fixed, I can also confirm the perft counts.

[RubiChess]

Old thread recycled...

Code: Select all

XFEN 04: 4r3/3k4/8/8/8/8/6PP/qR1K1R2 w KQ - 0 1
   +-a--b--c--d--e--f--g--h-+
 8 |   :::   :::[r]:::   :::|
 7 |:::   :::[k]:::   :::   |
 6 |   :::   :::   :::   :::|
 5 |:::   :::   :::   :::   |
 4 |   :::   :::   :::   :::|
 3 |:::   :::   :::   :::   |
 2 |   :::   :::   :::<P><P>|
 1 |[q]<R>:::<K>:::<R>:::   |
(w)+-a--*--c--*--e--*--g--h-+

Ply      Moves       [x] [ep]       [+] [++] Prom     Cstl    Sec
 1:         19         1    0         1    0    0        0   0.00
 2:        628        20    0        76    0    0        0   0.00
 3:      12858       499    0      1090    0    0      163   0.00
 4:     405636     15223    0     62483    0    0        0   0.01
 5:    8992652    286260    0    857746    0    0    81416   0.15
 6:  281330710  11668588    0  48470016 1034    0        0   4.33
 7: 6447669114 196804371    0 631079536    0    0 35649155 109.29

I'm implementing FRC in RubiChess these days and I'm in trouble with this special perft position. In ply 7 Rubi finds only 6447669103 instead of the correct 6447669114 moves so she misses 11 moves. Up to ply 6 everything is fine. Can anybody imagine which special tricky position can be on the board after 6 plies that has missing moves?

Regards, Andreas

[Evert]

Try a distributed perft, where you see the node counts for each node at ply 1. Then, make the move for which the node counts are off and repeat until you get to a position where you’re off at depth 1.

[RubiChess]

Try a distributed perft, where you see the node counts for each node at ply 1. Then, make the move for which the node counts are off and repeat until you get to a position where you’re off at depth 1.

Okay. But for this idea I need some reference data e.g. from an engine that does it correct, right? Will search for an engine that can output perft nodes per move at ply1... Ethereal will be my first bet.

Andreas

[Evert]

SjaakII can do that. “Perft 6 1” does a distributed perft to depth 6 and outputs node counts for every move at ply 1.

[RubiChess]

SjaakII can do that. “Perft 6 1” does a distributed perft to depth 6 and outputs node counts for every move at ply 1.

Okay, thanks. I just noticed it is yours
Already did the very few changes needed in Ethereal and distributed perft is running... But I will have a look at Sjaakll later.

Andreas