Perft figures for a few variants

[ilari]

I need to verify move generation + makemove/undomove for the following variants:
- losers chess: http://www.freechess.org/Help/HelpFiles/losers.html
- atomic chess: http://www.freechess.org/Help/HelpFiles/atomic.html
- crazyhouse: http://www.freechess.org/Help/HelpFiles/crazyhouse.html
- Shogi: http://en.wikipedia.org/wiki/Shogi
- Xianqi: http://en.wikipedia.org/wiki/Xiangqi

Does anyone have some perft figures for these variants, or are there freely available applications (engines?) that can help?

[TonyJH]

I have values for three of those variants. I haven't confirmed all of these with other programs.
http://tonyjh.com/chess/technical/

Xiangqi:

ply=1, positions=44
ply=2, positions=1920
ply=3, positions=79666
ply=4, positions=3290240
ply=5, positions=133312995
ply=6, positions=5392831844

Shogi:

ply=1, positions=30
ply=2, positions=900
ply=3, positions=25470
ply=4, positions=719731
ply=5, positions=19861490
ply=6, positions=547581517

Crazyhouse:

ply=1, positions=20
ply=2, positions=400
ply=3, positions=8902
ply=4, positions=197281
ply=5, positions=4888832
ply=6, positions=120812942

[ilari]

Okay, now my Crazyhouse numbers seem to be correct. But I can't figure out what's wrong with my Shogi perft. This is what I get for perft 4 in the starting position:

Code: Select all

FEN: lnsgkgsnl/1b5r1/ppppppppp/9/9/9/PPPPPPPPP/1B5R1/LNSGKGSNL w 
l n s g k g s n l 
. b . . . . . r . 
p p p p p p p p p 
. . . . . . . . . 
. . . . . . . . . 
. . . . . . . . . 
P P P P P P P P P 
. B . . . . . R . 
L N S G K G S N L 

i1i2: 23772
g1g2: 19527
g1f2: 20376
f1g2: 19527
f1e2: 21225
f1f2: 21225
e1e2: 22923
e1f2: 22074
e1d2: 23772
d1e2: 21225
d1c2: 22923
d1d2: 22923
c1c2: 23772
c1d2: 22923
a1a2: 25470
h2i2: 25472
h2c2: 24623
h2d2: 23774
h2e2: 23774
h2f2: 23774
h2g2: 24623
i3i4: 27168
h3h4: 26319
g3g4: 26387
f3f4: 25412
e3e4: 25467
d3d4: 25470
c3c4: 30286
b3b4: 25470
a3a4: 28015

Perft: 719691

But you have a value of 719731. Drops can be ignored at this depth, so this should be an easy one to fix. Is there a "perft" or "divide" command for TJshogi so that I could try to find out where the problem is?

[hgm]

Your perft counts are OK, but that is not the inital position of Shogi!

[ilari]

Your perft counts are OK, but that is not the inital position of Shogi!

I know that the colors should be reversed, but that shouldn't affect the perft counts. Is there something else wrong with the position, or are Tony's numbers incorrect?

[Kirill Kryukov]

Your perft counts are OK, but that is not the inital position of Shogi!

I know that the colors should be reversed, but that shouldn't affect the perft counts. Is there something else wrong with the position, or are Tony's numbers incorrect?

Black B and R should be swapped.

[ilari]

Your perft counts are OK, but that is not the inital position of Shogi!

I know that the colors should be reversed, but that shouldn't affect the perft counts. Is there something else wrong with the position, or are Tony's numbers incorrect?

Black B and R should be swapped.

Thanks, now all seems well. I misinterpreted "The bishop in the same file as the left knight and the rook in the same file as the right knight".

[ilari]

I just calculated perft 7 for Shogi. Can anyone verify this?

Code: Select all

FEN: lnsgkgsnl/1r5b1/ppppppppp/9/9/9/PPPPPPPPP/1B5R1/LNSGKGSNL w 

l n s g k g s n l 
. r . . . . . b . 
p p p p p p p p p 
. . . . . . . . . 
. . . . . . . . . 
. . . . . . . . . 
P P P P P P P P P 
. B . . . . . R . 
L N S G K G S N L 

i1i2: 441683687
g1g2: 300723199
g1f2: 341308698
f1g2: 299692898
f1e2: 370180725
f1f2: 376415409
e1e2: 456918050
e1f2: 405647471
e1d2: 479816613
d1e2: 362201645
d1c2: 427288168
d1d2: 442111933
c1c2: 477194778
c1d2: 439033899
a1a2: 550625810
h2i2: 538466257
h2c2: 488208990
h2d2: 467407795
h2e2: 481615976
h2f2: 485819793
h2g2: 521483691
i3i4: 666233156
h3h4: 595322898
g3g4: 622076911
f3f4: 563935223
e3e4: 565456101
d3d4: 551085704
c3c4: 1075043596
b3b4: 551306103
a3a4: 741964430

Perft: 15086269607

[TonyJH]

I just tried perft 7 and got the same number, 15086269607 (using a version of TJshogi that supports perft).

Could you try this position?

Code: Select all

WB FEN:  7lk/9/8S/9/9/9/9/7L1/8K[P] w 0 1
(white holds a pawn)
(SFEN: 7lk/9/8S/9/9/9/9/7L1/8K b P 1)

 .  .  .  .  .  .  .  l  k
 .  .  .  .  .  .  .  .  .
 .  .  .  .  .  .  .  .  S
 .  .  .  .  .  .  .  .  .
 .  .  .  .  .  .  .  .  .
 .  .  .  .  .  .  .  .  .
 .  .  .  .  .  .  .  .  .
 .  .  .  .  .  .  .  L  .
 .  .  .  .  .  .  .  .  K

ply=1, positions=85
ply=2, positions=639
ply=3, positions=10786
ply=4, positions=167089
ply=5, positions=3459265

If white was allowed to drop a pawn with mate, this would be a mate-in-1, but since that's not allowed, it's a mate-in-2.
If perft accounts for this rule, first ply has 85 legal moves (unless I made a mistake). Otherwise you will count 86.

It seems that perft 7 from the starting position never encounters this rule, because I get the same results whether or not this rule is followed.

[ilari]

I just tried perft 7 and got the same number, 15086269607 (using a version of TJshogi that supports perft).

Could you try this position?
...

I can confirm those numbers up to ply 4, but my ply 5 number is different:

Code: Select all

FEN: 7lk/9/8S/9/9/9/9/7L1/8K w P

. . . . . . . l k 
. . . . . . . . . 
. . . . . . . . S 
. . . . . . . . . 
. . . . . . . . . 
. . . . . . . . . 
. . . . . . . . . 
. . . . . . . L . 
. . . . . . . . K 

p@h1: 24855
p@g1: 16620
p@f1: 16781
p@e1: 16781
p@d1: 16781
p@c1: 16781
p@b1: 16781
p@a1: 16781
p@i2: 15206
p@g2: 16443
p@f2: 16584
p@e2: 16584
p@d2: 16584
p@c2: 16584
p@b2: 16584
p@a2: 16584
p@i3: 16525
p@h3: 18444
p@g3: 16483
p@f3: 16584
p@e3: 16584
p@d3: 16584
p@c3: 16584
p@b3: 16584
p@a3: 16584
p@i4: 16730
p@h4: 11361
p@g4: 16620
p@f4: 16584
p@e4: 16584
p@d4: 16584
p@c4: 16584
p@b4: 16584
p@a4: 16584
p@i5: 16486
p@h5: 12172
p@g5: 16618
p@f5: 16685
p@e5: 16685
p@d5: 16685
p@c5: 16685
p@b5: 16685
p@a5: 16685
p@i6: 15488
p@h6: 21915
p@g6: 18665
p@f6: 18738
p@e6: 18738
p@d6: 18738
p@c6: 18738
p@b6: 18738
p@a6: 18536
p@h7: 18755
p@g7: 18210
p@f7: 18637
p@e7: 18637
p@d7: 18637
p@c7: 18637
p@b7: 18637
p@a7: 18435
p@h8: 15097
p@g8: 16684
p@f8: 16786
p@e8: 16786
p@d8: 16786
p@c8: 16786
p@b8: 16786
p@a8: 16685
i1h1: 91255
i1i2: 144368
h2h8+l: 56775
h2h7+l: 59404
h2h9+l: 763212
h2h8: 56775
h2h7: 58192
h2h6: 69773
h2h5: 66984
h2h4: 72829
h2h3: 137829
i7i8+s: 124322
i7h6+s: 110968
i7h8+s: 117869
i7i8: 124322
i7h6: 116590
i7h8: 124198

Perft: 3458811