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Regression Tests

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Brad Knox edited this page Jul 14, 2022 · 239 revisions

All of the information below has been generated from the results of tests performed on the Fishtest framework. All data and graphs can be downloaded here. Please get involved if you have questions or suggestions!

Current Testing Criteria
  • 1 Thread 60 seconds + 0.6 seconds for 60,000 games (21/11/2019 - current)
  • 8 Threads 30 seconds + 0.3 seconds for 40,000 games (13/12/2018 - current)
  • 8moves_v3.pgn opening book (09/11/2013 - current)
Past Testing Criteria
  • 1 Thread 60 seconds + 0.6 seconds for 40,000 games (02/01/2016 - 21/11/2019)
  • 1 Thread 60 seconds + 0.5 seconds for 40,000 games (13/10/2013 - 02/01/2016)
  • 1 Thread 60 seconds + 0.5 seconds for 20,000 games (04/03/2013 - 13/10/2013)
  • 8moves_GM.pgn opening book (10/04/13 - 01/11/13)
  • varied.bin opening book (04/03/13 - 07/04/13)

Current Development

Current

Date Version 1 Thread 8 Threads
18/04/22 Stockfish 15 Stockfish Logo
Bench: 8129754
14/05/22 master vs Stockfish 15
Bench: 6481017
SE depth scaling using the previous depth
[differences] 9 		Elo: 4.54 ±0.8
[0-2]: [18, 1850, 25507, 2580, 45]
nElo: 16.29 ±2.8   PairsRatio: 1.41
[raw statistics] 		Elo: 3.12 ±0.8
[0-2]: [5, 803, 18029, 1154, 9]
nElo: 13.92 ±3.4   PairsRatio: 1.44
[raw statistics]
16/06/22 master vs Stockfish 15
Bench: 5845802
Simplify away condition in ttSave in probCut
[differences] 25 		Elo: 5.72 ±0.8
[0-2]: [31, 1838, 25288, 2799, 44]
nElo: 19.99 ±2.8   PairsRatio: 1.52
[raw statistics]
13/07/22 master vs Stockfish 15
Bench: 5905619
Update default net to nn-ad9b42354671.nnue
[differences] 34 		Elo: 5.70 ±0.8
[0-2]: [42, 1867, 25207, 2832, 52]
nElo: 19.67 ±2.8   PairsRatio: 1.51
[raw statistics] 		Elo: 4.86 ±0.8
[0-2]: [3, 734, 17975, 1276, 12]
nElo: 21.46 ±3.3   PairsRatio: 1.75
[raw statistics]

Fishtest Progression

Total

Version Progression

1 Thread 8 Threads
Dailly1 Daily8

30 Day Average

1 Thread 8 Threads
Thirty1 Thirty8

Draw Percentage vs Elo

1 Thread 8 Threads
DvE1 DvE8

Fishtest History

Stockfish 3 Development (01/03/13 - 30/04/13)
Date Version 1 Thread
22/09/12 Stockfish 2.3.1 Stockfish Logo
Bench: 5423738
01/03/13 Fishtest Introduced
04/03/13 master vs Stockfish 2.3.1
Bench: 4968764
Increase see prune depth
[differences] 226 		Elo: 15.00 ±2.8
[0-1]: [2906, 13325, 3769]
nElo: 26.02 ±4.8
[raw statistics]
11/03/13 master vs Stockfish 2.3.1
Bench: 4968764
Be more aggressive on trying to finish iterations
[differences] 227 		Elo: 15.49 ±2.8
[0-1]: [3016, 13077, 3907]
nElo: 26.38 ±4.8
[raw statistics]
11/03/13 master vs Stockfish 2.3.1
Bench: 4968764
Check for easy move just once
[differences] 228 		Elo: 13.42 ±2.8
[0-1]: [2974, 13280, 3746]
nElo: 23.19 ±4.8
[raw statistics]
16/03/13 master vs Stockfish 2.3.1
Bench: 5442365
Further increase SEE prune depth
[differences] 232 		Elo: 17.77 ±2.8
[0-1]: [2897, 13184, 3919]
nElo: 30.53 ±4.8
[raw statistics]
24/03/13 master vs Stockfish 2.3.1
Bench: 4985829
Update bestValue when futility pruning (2)
[differences] 237 		Elo: 16.71 ±2.8
[0-1]: [2874, 13291, 3835]
nElo: 28.92 ±4.8
[raw statistics]
30/03/13 master vs Stockfish 2.3.1
Bench: 4781239
Set IID half way between d/2 and d-4
[differences] 241 		Elo: 18.76 ±2.8
[0-1]: [2824, 13273, 3903]
nElo: 32.46 ±4.8
[raw statistics]
03/04/13 master vs Stockfish 2.3.1
Bench: 4705335
Double Impact of Gain tables
[differences] 242 		Elo: 15.44 ±2.8
[0-1]: [3040, 13032, 3928]
nElo: 26.21 ±4.8
[raw statistics]
06/04/13 master vs Stockfish 2.3.1
Bench: 4361224
Increase null verification threshold to 12 plies
[differences] 249 		Elo: 17.11 ±2.8
[0-1]: [2774, 12861, 3727]
nElo: 29.62 ±4.9
[raw statistics]
07/04/13 master vs Stockfish 2.3.1
Bench: 5473339
Rescale UCI parameters to 100
[differences] 252 		Elo: 19.02 ±2.8
[0-1]: [2948, 13010, 4042]
nElo: 32.29 ±4.8
[raw statistics]
10/04/13 master vs Stockfish 2.3.1
Bench: 5157061
De-templetize Position::is_draw()
[differences] 257 		Elo: 24.13 ±2.8
[0-1]: [2791, 13031, 4178]
nElo: 41.10 ±4.8
[raw statistics]
19/04/13 master vs Stockfish 2.3.1
Bench: 5274705
Skip a couple of popcount in previous patch
[differences] 262 		Elo: 28.27 ±2.9
[0-1]: [2754, 12868, 4378]
nElo: 47.69 ±4.9
[raw statistics]
26/04/13 master vs Stockfish 2.3.1
Bench: 4311634
Fix a crash introduced few days ago
[differences] 270 		Elo: 33.67 ±2.9
[0-1]: [2642, 12784, 4574]
nElo: 56.61 ±4.9
[raw statistics]
28/04/13 master vs Stockfish 2.3.1
Bench: 4176431
Temporary revert "Expose EvalInfo struct to search"
[differences] 273 		Elo: 30.86 ±2.9
[0-1]: [2721, 12786, 4493]
nElo: 51.82 ±4.9
[raw statistics]
30/04/13 Stockfish 3 Stockfish Logo Chart
Bench: 4176431
Official Release
[differences] 275
Stockfish 4 Development (30/04/13 - 20/08/13)
Date Version 1 Thread
30/04/13 Stockfish 3 Stockfish Logo
Bench: 4176431
16/05/13 master vs Stockfish 3
Bench: 4327405
Use two counter moves instead of one
[differences] 28 		Elo: 22.11 ±3.0
[0-1]: [3212, 12305, 4483]
nElo: 35.78 ±4.8
[raw statistics]
23/05/13 master vs Stockfish 3
Bench: 4821467
Bunch of 3 small patches
[differences] 33 		Elo: 26.70 ±2.1
[0-1]: [6435, 24062, 9503]
nElo: 42.53 ±3.4
[raw statistics]
31/05/13 master vs Stockfish 3
Bench: 4931544
Passed pawn tuning
[differences] 38 		Elo: 29.50 ±2.2
[0-1]: [6588, 23436, 9976]
nElo: 46.13 ±3.4
[raw statistics]
23/06/13 master vs Stockfish 3
Bench: 4609948
Fix some stale comments
[differences] 72 		Elo: 35.47 ±2.2
[0-1]: [6196, 23539, 10265]
nElo: 55.80 ±3.4
[raw statistics]
03/07/13 master vs Stockfish 3
Bench: 4507288
Simplify aspiration window code
[differences] 88 		Elo: 37.36 ±2.2
[0-1]: [6223, 23269, 10508]
nElo: 58.35 ±3.4
[raw statistics]
13/07/13 master vs Stockfish 3
Bench: 4558173
Fully qualify memset and memcpy
[differences] 100 		Elo: 39.27 ±3.1
[0-1]: [3052, 11645, 5303]
nElo: 61.44 ±4.9
[raw statistics]
19/07/13 master vs Stockfish 3
Bench: 4769737
Halve king eval margin
[differences] 110 		Elo: 39.83 ±3.1
[0-1]: [3067, 11583, 5350]
nElo: 62.10 ±4.9
[raw statistics]
25/07/13 master vs Stockfish 3
Bench: 4727133
Rewrite pawn shield and storm code
[differences] 133 		Elo: 48.84 ±3.3
[0-1]: [3203, 10801, 5996]
nElo: 73.11 ±4.9
[raw statistics]
03/08/13 master vs Stockfish 3
Bench: 4424151
Streamline time computation
[differences] 147 		Elo: 50.95 ±3.2
[0-1]: [3056, 10976, 5968]
nElo: 77.14 ±4.9
[raw statistics]
18/08/13 master vs Stockfish 3
Bench: 4132374
Further tweak movecount pruning
[differences] 162 		Elo: 56.66 ±3.3
[0-1]: [2988, 10791, 6221]
nElo: 85.22 ±5.0
[raw statistics]
20/08/13 Stockfish 4 Stockfish Logo Chart
Bench: 4132374
Official Release
[differences] 165
Stockfish DD Development (20/08/13 - 29/11/13)
Date Version 1 Thread
20/08/13 Stockfish 4 Stockfish Logo
Bench: 4132374
29/08/13 master vs Stockfish 4
Bench: 4620975
Enable LMR for dangerous moves
[differences] 12 		Elo: 16.18 ±2.9
[0-1]: [3221, 12627, 4152]
nElo: 26.72 ±4.8
[raw statistics]
01/09/13 master vs Stockfish 4
Bench: 3453945
Don't use lpthread for Android
[differences] 18 		Elo: 19.30 ±2.9
[0-1]: [3083, 12724, 4193]
nElo: 32.11 ±4.8
[raw statistics]
05/09/13 master vs Stockfish 4
Bench: 4633330
Do not prune useless checks in QS
[differences] 23 		Elo: 23.80 ±2.9
[0-1]: [2932, 12768, 4300]
nElo: 39.78 ±4.8
[raw statistics]
07/09/13 master vs Stockfish 4
Bench: 3864419
Remove unreachable values in mobility table
[differences] 27 		Elo: 27.66 ±2.9
[0-1]: [2766, 12879, 4355]
nElo: 46.68 ±4.9
[raw statistics]
11/09/13 master vs Stockfish 4
Bench: 4554576
Extend checks more when below alpha
[differences] 35 		Elo: 24.87 ±2.9
[0-1]: [2824, 12923, 4253]
nElo: 42.04 ±4.8
[raw statistics]
12/09/13 master vs Stockfish 4
Bench: 4554579
Revert "Move draw by material check"
[differences] 37 		Elo: 24.34 ±2.9
[0-1]: [2825, 12951, 4224]
nElo: 41.22 ±4.8
[raw statistics]
13/09/13 master vs Stockfish 4
Bench: 3846852
Increase passed bonus for having more pieces
[differences] 38 		Elo: 26.21 ±2.9
[0-1]: [2871, 12752, 4377]
nElo: 43.80 ±4.8
[raw statistics]
16/09/13 master vs Stockfish 4
Bench: 3884003
Fix time parameters for blitz games
[differences] 47 		Elo: 31.56 ±2.1
[0-1]: [5588, 25200, 9212]
nElo: 52.33 ±3.4
[raw statistics]
23/09/13 master vs Stockfish 4
Bench: 3529630
Update disabled warnings for Intel compiler
[differences] 54 		Elo: 34.03 ±2.1
[0-1]: [5449, 25197, 9354]
nElo: 56.49 ±3.4
[raw statistics]
28/09/13 master vs Stockfish 4
Bench: 3172206
Drop 'is' prefix from query functions
[differences] 62 		Elo: 33.49 ±2.9
[0-1]: [2571, 12936, 4493]
nElo: 56.93 ±4.9
[raw statistics]
29/09/13 master vs Stockfish 4
Bench: 8336338
Add more depth/positions to bench
[differences] 63 		Elo: 33.90 ±2.0
[0-1]: [5292, 25525, 9183]
nElo: 56.93 ±3.4
[raw statistics]
08/10/13 master vs Stockfish 4
Bench: 8340585
Use TT refined value to stand pat
[differences] 66 		Elo: 36.58 ±2.9
[0-1]: [2623, 12656, 4721]
nElo: 61.07 ±4.9
[raw statistics]
08/10/13 master vs Stockfish 4
Bench: 8340585
Increase slowmover and reduce instability
[differences] 67 		Elo: 38.91 ±2.1
[0-1]: [5102, 25335, 9563]
nElo: 65.11 ±3.5
[raw statistics]
09/10/13 master vs Stockfish 4
Bench: 8279065
Smoother transition for LMR
[differences] 68 		Elo: 39.29 ±2.1
[0-1]: [5071, 25354, 9575]
nElo: 65.80 ±3.4
[raw statistics]
14/10/13 master vs Stockfish 4
Bench: 7700683
Double king safety weights
[differences] 75 		Elo: 43.64 ±2.9
[0-1]: [2432, 12637, 4931]
nElo: 73.12 ±4.9
[raw statistics]
18/10/13 master vs Stockfish 4
Bench: 8440524
Score chain pawn also by rank
[differences] 78 		Elo: 49.51 ±2.1
[0-1]: [4821, 24696, 10483]
nElo: 81.68 ±3.5
[raw statistics]
19/10/13 master vs Stockfish 4
Bench: 9160831
Further increase safe checks bonus
[differences] 80 		Elo: 50.11 ±2.1
[0-1]: [4817, 24636, 10547]
nElo: 82.54 ±3.5
[raw statistics]
20/10/13 master vs Stockfish 4
Bench: 9294116
Further improve chain pawn evaluation
[differences] 84 		Elo: 49.72 ±3.1
[0-1]: [2677, 11803, 5520]
nElo: 79.12 ±4.9
[raw statistics]
22/10/13 master vs Stockfish 4
Bench: 8455956
Tweak again chain pawn bonus
[differences] 87 		Elo: 53.85 ±3.0
[0-1]: [2425, 12075, 5500]
nElo: 87.51 ±4.9
[raw statistics]
24/10/13 master vs Stockfish 4
Bench: 8291883
Retire mirror()
[differences] 94 		Elo: 55.18 ±3.0
[0-1]: [2385, 12080, 5535]
nElo: 89.82 ±4.9
[raw statistics]
28/10/13 master vs Stockfish 4
Bench: 8029334
Tweak bishop pair and knight weight
[differences] 96 		Elo: 52.84 ±2.1
[0-1]: [4866, 24231, 10903]
nElo: 86.04 ±3.5
[raw statistics]
01/11/13 master vs Stockfish 4
Bench: 7995098
Set timer to a fixed interval
[differences] 98 		Elo: 59.73 ±3.0
[0-1]: [2324, 11947, 5729]
nElo: 96.77 ±5.0
[raw statistics]
09/11/13 master vs Stockfish 4
Bench: 7243575
Futility pruning simplification
[differences] 106 		Elo: 60.68 ±3.0
[0-1]: [2198, 12146, 5656]
nElo: 99.73 ±5.0
[raw statistics]
10/11/13 master vs Stockfish 4
Bench: 9282549
Remove opposed flag for doubled pawns
[differences] 113 		Elo: 61.23 ±2.1
[0-1]: [4333, 24357, 11310]
nElo: 100.91 ±3.5
[raw statistics]
11/11/13 master vs Stockfish 4
Bench: 8331357
Simplify generate<EVASIONS>
[differences] 116 		Elo: 63.85 ±2.1
[0-1]: [4185, 24361, 11454]
nElo: 105.53 ±3.5
[raw statistics]
29/11/13 master vs Stockfish 4
Bench: 8596156
Add support for PPC 64bit on Linux
[differences] 123 		Elo: 67.44 ±2.1
[0-1]: [4119, 24094, 11787]
nElo: 110.87 ±3.5
[raw statistics]
29/11/13 Stockfish DD Stockfish Logo Chart
Bench: 8596156
Official Release
[differences] 124
Stockfish 5 Development (29/11/13 - 31/05/14)
Date Version 1 Thread
29/11/13 Stockfish DD Stockfish Logo
Bench: 8596156
09/12/13 master vs Stockfish DD
Bench: 7869223
Research at intermediate depth if LMR is very high
[differences] 23 		Elo: 7.94 ±1.9
[0-1]: [5662, 27762, 6576]
nElo: 14.37 ±3.4
[raw statistics]
19/12/13 master vs Stockfish DD
Bench: 7425809
Faster and simplified threat eval
[differences] 29 		Elo: 11.35 ±1.9
[0-1]: [5766, 27162, 7072]
nElo: 20.06 ±3.4
[raw statistics]
23/12/13 master vs Stockfish DD
Bench: 6835416
Loosened trigger condition for king safety
[differences] 31 		Elo: 18.62 ±2.0
[0-1]: [5619, 26620, 7761]
nElo: 32.31 ±3.4
[raw statistics]
29/12/13 master vs Stockfish DD
Bench: 7762310
Retire asymmThreshold
[differences] 36 		Elo: 19.54 ±2.0
[0-1]: [5580, 26593, 7827]
nElo: 33.87 ±3.4
[raw statistics]
02/01/14 master vs Stockfish DD
Bench: 7602383
Ensure move_importance() is non-zero
[differences] 46 		Elo: 25.36 ±2.0
[0-1]: [5371, 26343, 8286]
nElo: 43.67 ±3.4
[raw statistics]
08/01/14 master vs Stockfish DD
Bench: 8502826
Position::gives_check - use ci.ksq
[differences] 55 		Elo: 29.85 ±2.0
[0-1]: [5165, 26242, 8593]
nElo: 51.32 ±3.4
[raw statistics]
14/01/14 master vs Stockfish DD
Bench: 7205153
Introduce 'follow up' moves
[differences] 59 		Elo: 29.84 ±2.0
[0-1]: [5222, 26129, 8649]
nElo: 51.09 ±3.4
[raw statistics]
19/01/14 master vs Stockfish DD
Bench: 7804908
Small simplification to Position::see
[differences] 64 		Elo: 32.49 ±2.0
[0-1]: [5088, 26094, 8818]
nElo: 55.65 ±3.4
[raw statistics]
29/01/14 master vs Stockfish DD
Bench: 6875743
Tweak bishop PSQT tables
[differences] 70 		Elo: 36.66 ±2.0
[0-1]: [4905, 25985, 9110]
nElo: 62.70 ±3.4
[raw statistics]
09/02/14 master vs Stockfish DD
Bench: 8347121
Faster handling of king captures in Position::see
[differences] 79 		Elo: 38.63 ±2.0
[0-1]: [4956, 25659, 9385]
nElo: 65.38 ±3.4
[raw statistics]
22/02/14 master vs Stockfish DD
Bench: 8430785
Fix a warning with Intel compiler
[differences] 99 		Elo: 38.93 ±2.0
[0-1]: [4944, 25649, 9407]
nElo: 65.87 ±3.4
[raw statistics]
26/02/14 master vs Stockfish DD
Bench: 7990513
Dynamic draw value
[differences] 100 		Elo: 39.25 ±2.1
[0-1]: [5164, 25172, 9664]
nElo: 65.32 ±3.4
[raw statistics]
14/03/14 master vs Stockfish DD
Bench: 7451319
Depth dependent aspiration window delta
[differences] 122 		Elo: 40.85 ±2.0
[0-1]: [4925, 25469, 9606]
nElo: 68.77 ±3.5
[raw statistics]
24/03/14 master vs Stockfish DD
Bench: 7682173
Simplify TT replace strategy
[differences] 138 		Elo: 43.70 ±2.1
[0-1]: [4887, 25221, 9892]
nElo: 73.08 ±3.5
[raw statistics]
08/04/14 master vs Stockfish DD
Bench: 7533692
Restrict queen mobility to safe squares
[differences] 159 		Elo: 47.70 ±2.1
[0-1]: [4689, 25165, 10146]
nElo: 79.86 ±3.5
[raw statistics]
12/04/14 master vs Stockfish DD
Bench: 6921356
Move args parsing to UCI::loop
[differences] 174 		Elo: 49.21 ±2.1
[0-1]: [4717, 24938, 10345]
nElo: 81.84 ±3.5
[raw statistics]
21/04/14 master vs Stockfish DD
Bench: 7384368
Reset DrawValue[] before new search
[differences] 184 		Elo: 54.53 ±2.1
[0-1]: [4742, 24289, 10969]
nElo: 89.09 ±3.5
[raw statistics]
25/04/14 master vs Stockfish DD
Bench: 7905850
Speed up picking of killers
[differences] 191 		Elo: 57.08 ±2.2
[0-1]: [4858, 23771, 11371]
nElo: 91.87 ±3.5
[raw statistics]
04/05/14 master vs Stockfish DD
Bench: 8802105
Revert dynamic contempt
[differences] 216 		Elo: 53.27 ±2.2
[0-1]: [5183, 23549, 11268]
nElo: 84.84 ±3.5
[raw statistics]
13/05/14 master vs Stockfish DD
Bench: 8739659
Drop to qsearch at low depth in razoring
[differences] 227 		Elo: 57.15 ±1.8
[0-1]: [7289, 35641, 17070]
nElo: 91.95 ±2.9
[raw statistics]
17/05/14 master vs Stockfish DD
Bench: 8732553
Fix an off-by-one bug in extract_pv_from_tt
[differences] 229 		Elo: 55.26 ±2.2
[0-1]: [5108, 23475, 11417]
nElo: 87.95 ±3.5
[raw statistics]
24/05/14 master vs Stockfish DD
Bench: 7396783
Fix a warning with Intel compiler
[differences] 234 		Elo: 53.28 ±2.1
[0-1]: [4858, 24198, 10944]
nElo: 86.68 ±3.5
[raw statistics]
31/05/14 Stockfish 5 Stockfish Logo Chart
Bench: 8732553
Official Release
[differences] 236
Stockfish 6 Development (31/05/14 - 27/01/15)
Date Version 1 Thread
31/05/14 Stockfish 5 Stockfish Logo
Bench: 8732553
03/06/14 master vs Stockfish 5
Bench: 8205159
Symmetric King Safety: take 2
[differences] 8 		Elo: 5.35 ±1.8
[0-1]: [5386, 28612, 6002]
nElo: 10.03 ±3.4
[raw statistics]
11/06/14 master vs Stockfish 5
Bench: 7875814
Simplify pawn threats and merge into ThreatenedByPawn[]
[differences] 22 		Elo: 8.30 ±2.0
[0-1]: [4589, 24491, 5413]
nElo: 15.43 ±3.7
[raw statistics]
29/06/14 master vs Stockfish 5
Bench: 8759675
Fix Singular extension condition to handle mate scores
[differences] 46 		Elo: 10.78 ±1.8
[0-1]: [5152, 28455, 6393]
nElo: 20.10 ±3.4
[raw statistics]
22/07/14 master vs Stockfish 5
Bench: 7831429
Outpost tuning
[differences] 62 		Elo: 19.63 ±1.8
[0-1]: [4775, 28192, 7033]
nElo: 36.29 ±3.4
[raw statistics]
06/08/14 master vs Stockfish 5
Bench: 7461881
Remove insufficient material rule
[differences] 73 		Elo: 19.68 ±1.8
[0-1]: [4737, 28263, 7000]
nElo: 36.49 ±3.4
[raw statistics]
04/09/14 master vs Stockfish 5
Bench: 7461881
Small tweak to idle_loop()
[differences] 82 		Elo: 15.90 ±1.8
[0-1]: [4986, 28199, 6815]
nElo: 29.35 ±3.4
[raw statistics]
27/09/14 master vs Stockfish 5
Bench: 6545733
Remove use of half-ply reductions
[differences] 93 		Elo: 22.80 ±1.9
[0-1]: [4664, 28051, 7285]
nElo: 41.96 ±3.4
[raw statistics]
15/10/14 master vs Stockfish 5
Bench: 7328585
Document why initing eval tables
[differences] 108 		Elo: 27.58 ±1.9
[0-1]: [4613, 27605, 7782]
nElo: 49.96 ±3.4
[raw statistics]
01/11/14 master vs Stockfish 5
Bench: 6564212
Merge pull request #89 from official-stockfish/pull_no_pretty
[differences] 129 		Elo: 31.00 ±1.9
[0-1]: [4484, 27472, 8044]
nElo: 55.96 ±3.4
[raw statistics]
10/11/14 master vs Stockfish 5
Bench: 6807896
Profile Build with Hash=16
[differences] 148 		Elo: 36.21 ±1.9
[0-1]: [4357, 27132, 8511]
nElo: 64.71 ±3.4
[raw statistics]
25/11/14 master vs Stockfish 5
Bench: 8255966
Bitbase index() from ADD to OR
[differences] 168 		Elo: 39.02 ±1.9
[0-1]: [4151, 27225, 8624]
nElo: 70.14 ±3.4
[raw statistics]
07/12/14 master vs Stockfish 5
Bench: 9324905
Simpler PRNG and faster magics search
[differences] 181 		Elo: 41.42 ±1.9
[0-1]: [4108, 27038, 8854]
nElo: 74.04 ±3.4
[raw statistics]
22/12/14 master vs Stockfish 5
Bench: 9498821
Prefer names to numbers in storm code
[differences] 197 		Elo: 46.26 ±1.9
[0-1]: [4011, 26683, 9306]
nElo: 81.89 ±3.4
[raw statistics]
07/01/15 master vs Stockfish 5
Bench: 7604776
Assorted formatting and comment tweaks in position.h
[differences] 213 		Elo: 52.10 ±2.0
[0-1]: [3913, 26688, 9948]
nElo: 91.46 ±3.4
[raw statistics]
18/01/15 master vs Stockfish 5
Bench: 8080602
Stockfish 6 Release Candidate 1
[differences] 228 		Elo: 51.71 ±1.9
[0-1]: [3723, 26644, 9633]
nElo: 91.89 ±3.5
[raw statistics]
27/01/15 Stockfish 6 Stockfish Logo Chart
Bench: 8918745
Official Release
[differences] 236
Stockfish 7 Development (27/01/15 - 02/01/16)
Date Version 1 Thread
27/01/15 Stockfish 6 Stockfish Logo
Bench: 8918745
08/02/15 master vs Stockfish 6
Bench: 7699138
Pawn Center Bind Bonus
[differences] 12 		Elo: 7.50 ±2.0
[0-1]: [6423, 26291, 7286]
nElo: 12.81 ±3.4
[raw statistics]
19/03/15 master vs Stockfish 6
Bench: 8226843
Retire ConditionVariable
[differences] 123 		Elo: 15.92 ±1.8
[0-1]: [4796, 28576, 6628]
nElo: 29.89 ±3.4
[raw statistics]
29/03/15 master vs Stockfish 6
Bench: 7658627
Remove some difficult to understand C++11 constructs
[differences] 137 		Elo: 19.02 ±1.8
[0-1]: [4590, 28633, 6777]
nElo: 35.82 ±3.4
[raw statistics]
10/04/15 master vs Stockfish 6
Bench: 6985247
Allow Position::init() to be called more than once
[differences] 151 		Elo: 22.12 ±1.8
[0-1]: [4480, 28497, 7023]
nElo: 41.48 ±3.4
[raw statistics]
09/05/15 master vs Stockfish 6
Bench: 8787152
Smart TT save
[differences] 164 		Elo: 28.82 ±1.8
[0-1]: [4197, 28295, 7508]
nElo: 53.80 ±3.4
[raw statistics]
07/06/15 master vs Stockfish 6
Bench: 6716940
Simplify outpost evaluation
[differences] 176 		Elo: 27.85 ±1.9
[0-1]: [4501, 27798, 7701]
nElo: 50.86 ±3.4
[raw statistics]
16/07/15 master vs Stockfish 6
Bench: 6943812
Fix formatting of previous patch
[differences] 187 		Elo: 30.74 ±1.9
[0-1]: [4367, 27736, 7897]
nElo: 56.09 ±3.4
[raw statistics]
30/07/15 master vs Stockfish 6
Bench: 8040572
Simplify IID depth formula
[differences] 192 		Elo: 34.04 ±1.9
[0-1]: [4283, 27527, 8190]
nElo: 61.72 ±3.4
[raw statistics]
03/10/15 master vs Stockfish 6
Bench: 8073614
File based passed pawn bonus
[differences] 214 		Elo: 44.23 ±1.9
[0-1]: [3690, 27555, 8755]
nElo: 80.99 ±3.4
[raw statistics]
25/10/15 master vs Stockfish 6
Bench: 8004751
Use atomics instead of volatile
[differences] 232 		Elo: 61.76 ±1.9
[0-1]: [3197, 26570, 10233]
nElo: 110.69 ±3.5
[raw statistics]
27/12/15 master vs Stockfish 6
Bench: 8355485
Stockfish 7 Beta 1
[differences] 267 		Elo: 62.62 ±1.6
[0-1]: [4472, 40358, 15170]
nElo: 113.94 ±2.8
[raw statistics]
02/01/16 Stockfish 7 Stockfish Logo Chart
Bench: 8355485
Official Release
[differences] 273
Stockfish 8 Development (02/01/16 - 01/11/16)
Date Version 1 Thread
02/01/16 Stockfish 7 Stockfish Logo
Bench: 8355485
28/01/16 master vs Stockfish 7
Bench: 7751425
Time management simplification
[differences] 16 		Elo: 4.93 ±1.5
[0-1]: [3814, 31804, 4382]
nElo: 10.90 ±3.4
[raw statistics]
10/03/16 master vs Stockfish 7
Bench: 8261839
Add follow up moves history for move ordering
[differences] 28 		Elo: 12.83 ±1.5
[0-1]: [3354, 31816, 4830]
nElo: 28.44 ±3.4
[raw statistics]
08/04/16 master vs Stockfish 7
Bench: 7482426
Small passed pawn simplification
[differences] 42 		Elo: 15.27 ±1.5
[0-1]: [3251, 31741, 5008]
nElo: 33.74 ±3.4
[raw statistics]
20/05/16 master vs Stockfish 7
Bench: 8428997
More detailed dependence of time allocation
[differences] 64 		Elo: 29.44 ±1.6
[0-1]: [2719, 31217, 6104]
nElo: 63.61 ±3.4
[raw statistics]
10/06/16 master vs Stockfish 7
Bench: 8276130
Stat Formula Tweak
[differences] 76 		Elo: 36.29 ±1.6
[0-1]: [2606, 30625, 6769]
nElo: 76.48 ±3.4
[raw statistics]
24/07/16 master vs Stockfish 7
Bench: 8145304
Allow null pruning at depth 1
[differences] 94 		Elo: 49.73 ±1.7
[0-1]: [2415, 29483, 8102]
nElo: 100.27 ±3.4
[raw statistics]
18/08/16 master vs Stockfish 7
Bench: 7662861
Remove a stale assignment
[differences] 101 		Elo: 52.59 ±1.7
[0-1]: [2413, 29165, 8422]
nElo: 104.74 ±3.4
[raw statistics]
07/09/16 master vs Stockfish 7
Bench: 6024713
Refactor previous patch
[differences] 124 		Elo: 66.53 ±1.8
[0-1]: [1893, 28647, 9460]
nElo: 131.97 ±3.3
[raw statistics]
07/10/16 master vs Stockfish 7
Bench: 6421663
Optimisation of Position::see and Position::see_sign
[differences] 149 		Elo: 76.60 ±1.8
[0-1]: [1571, 28179, 10250]
nElo: 151.24 ±3.3
[raw statistics]
01/11/16 Stockfish 8 Stockfish Logo Chart
Bench: 5926706
Official Release
[differences] 168
Stockfish 9 Development (01/11/16 - 31/01/18)
Date Version 1 Thread
01/11/16 Stockfish 8 Stockfish Logo
Bench: 5926706
31/12/16 master vs Stockfish 8
Bench: 5468995
Small eval cleanup and renaming
[differences] 55 		Elo: 5.21 ±1.5
[0-1]: [3656, 32088, 4256]
nElo: 11.72 ±3.4
[raw statistics]
29/01/17 master vs Stockfish 8
Bench: 5941174
Simplify TT penalty stat (#980)
[differences] 86 		Elo: 8.82 ±1.5
[0-1]: [3580, 31825, 4595]
nElo: 19.53 ±3.4
[raw statistics]
08/03/17 master vs Stockfish 8
Bench: 5803228
Helper functions to count material for both sides
[differences] 106 		Elo: 10.84 ±1.6
[0-1]: [3569, 31614, 4817]
nElo: 23.73 ±3.4
[raw statistics]
20/04/17 master vs Stockfish 8
Bench: 6581936
simplify logic for history based pruning
[differences] 127 		Elo: 15.17 ±1.6
[0-1]: [3430, 31395, 5175]
nElo: 32.82 ±3.4
[raw statistics]
07/05/17 master vs Stockfish 8
Bench: 6107863
Linear Protector bonus by distance
[differences] 144 		Elo: 20.25 ±1.6
[0-1]: [3258, 31155, 5587]
nElo: 43.35 ±3.4
[raw statistics]
21/06/17 master vs Stockfish 8
Bench: 5725676
Increase reduction if tt-move is a capture
[differences] 167 		Elo: 27.41 ±1.6
[0-1]: [2918, 31015, 6067]
nElo: 58.52 ±3.4
[raw statistics]
26/08/17 master vs Stockfish 8
Bench: 5965302
Improve multi-threaded mate finding
[differences] 218 		Elo: 29.32 ±1.6
[0-1]: [2886, 30860, 6254]
nElo: 62.17 ±3.4
[raw statistics]
02/10/17 master vs Stockfish 8
Bench: 5620312
Good bishops on the main diagonals
[differences] 237 		Elo: 32.61 ±1.6
[0-1]: [2688, 30881, 6431]
nElo: 69.44 ±3.4
[raw statistics]
03/11/17 master vs Stockfish 8
Bench: 5536775
Introduce capture history table for capture move sorting
[differences] 247 		Elo: 35.18 ±1.6
[0-1]: [2682, 30600, 6718]
nElo: 73.93 ±3.4
[raw statistics]
03/12/17 master vs Stockfish 8
Bench: 5051254
Use constexpr when makes sense
[differences] 261 		Elo: 43.31 ±1.7
[0-1]: [2406, 30227, 7367]
nElo: 90.06 ±3.3
[raw statistics]
23/01/18 master vs Stockfish 8
Bench: 5783344
Contempt 20
[differences] 286 		Elo: 57.25 ±1.9
[0-1]: [2917, 27634, 9449]
nElo: 106.75 ±3.4
[raw statistics]
31/01/18 Stockfish 9 Stockfish Logo Chart
Bench: 5023629
Official Release
[differences] 291
Stockfish 10 Development (31/01/18 - 29/11/18)
Date Version 1 Thread
31/01/18 Stockfish 9 Stockfish Logo
Bench: 5023629
28/02/18 master vs Stockfish 9
Bench: 5765806
Reintroduce depth 2 razoring (with additional margin)
[differences] 41 		Elo: 5.16 ±1.7
[0-1]: [5143, 30105, 5752]
nElo: 10.02 ±3.4
[raw statistics]
07/03/18 master vs Stockfish 9
Bench: 5544908
Simplification: use Arctan for the optimism S-curve
[differences] 53 		Elo: 6.94 ±1.7
[0-1]: [4813, 29575, 5612]
nElo: 13.60 ±3.4
[raw statistics]
13/03/18 master vs Stockfish 9
Bench: 5741807
Use intrinsics only for LSB/MSB
[differences] 64 		Elo: 13.03 ±1.7
[0-1]: [4463, 29574, 5963]
nElo: 25.59 ±3.4
[raw statistics]
26/03/18 master vs Stockfish 9
Bench: 5934103
Make kingRing always 8 squares
[differences] 75 		Elo: 13.77 ±1.7
[0-1]: [4339, 29737, 5924]
nElo: 27.26 ±3.4
[raw statistics]
03/04/18 master vs Stockfish 9
Bench: 4989125
Remove the Queen from the mobility area of minor pieces
[differences] 92 		Elo: 16.59 ±1.7
[0-1]: [4283, 29525, 6192]
nElo: 32.54 ±3.4
[raw statistics]
07/04/18 master vs Stockfish 9
Bench: 5170165
Reset negative statScore on fail high
[differences] 94 		Elo: 16.63 ±1.8
[0-1]: [4397, 29293, 6310]
nElo: 32.25 ±3.4
[raw statistics]
23/04/18 master vs Stockfish 9
Bench: 5549801
Alternative formula for dynamic contempt
[differences] 106 		Elo: 15.90 ±1.8
[0-1]: [4462, 29247, 6291]
nElo: 30.76 ±3.4
[raw statistics]
29/04/18 master vs Stockfish 9
Bench: 5254862
Always scale using pawn contribution
[differences] 112 		Elo: 14.61 ±1.7
[0-1]: [4430, 29459, 6111]
nElo: 28.54 ±3.4
[raw statistics]
03/05/18 master vs Stockfish 9
Bench: 5186783
Tweak the connected[] array value for pawns on rank 5
[differences] 116 		Elo: 18.52 ±1.8
[0-1]: [4385, 29100, 6515]
nElo: 35.63 ±3.4
[raw statistics]
13/05/18 master vs Stockfish 9
Bench: 5294316
Update search.cpp
[differences] 128 		Elo: 24.92 ±1.8
[0-1]: [4175, 28786, 7039]
nElo: 47.42 ±3.4
[raw statistics]
24/05/18 master vs Stockfish 9
Bench: 5167159
LMR Capture Tweak
[differences] 137 		Elo: 26.72 ±1.8
[0-1]: [4033, 28864, 7103]
nElo: 51.08 ±3.4
[raw statistics]
05/06/18 master vs Stockfish 9
Bench: 4326784
Call cycle detection before qsearch()
[differences] 148 		Elo: 28.16 ±1.8
[0-1]: [3971, 28823, 7206]
nElo: 53.79 ±3.4
[raw statistics]
11/06/18 master vs Stockfish 9
Bench: 4980482
Optimize an expression in endgame.cpp
[differences] 154 		Elo: 29.72 ±1.9
[0-1]: [4335, 27917, 7748]
nElo: 54.60 ±3.4
[raw statistics]
23/06/18 master vs Stockfish 9
Bench: 4557946
Another set of tuned values after one million games
[differences] 162 		Elo: 31.98 ±1.9
[0-1]: [4354, 27621, 8025]
nElo: 58.11 ±3.4
[raw statistics]
19/07/18 master vs Stockfish 9
Bench: 4817583
Better check evasion move sorting
[differences] 179 		Elo: 36.70 ±1.9
[0-1]: [4312, 27166, 8522]
nElo: 65.70 ±3.4
[raw statistics]
27/07/18 master vs Stockfish 9
Bench: 4905530
Simplify cmh pruning
[differences] 199 		Elo: 37.45 ±1.9
[0-1]: [4183, 27339, 8478]
nElo: 67.55 ±3.4
[raw statistics]
28/07/18 master vs Stockfish 9
Bench: 4883742
Increase the mg->eg gradient for the PawnlessFlank malus
[differences] 200 		Elo: 35.84 ±1.9
[0-1]: [4235, 27418, 8347]
nElo: 64.78 ±3.4
[raw statistics]
31/07/18 master vs Stockfish 9
Bench: 5591925
Small tweaks to recent code changes
[differences] 203 		Elo: 37.67 ±1.9
[0-1]: [4019, 27642, 8339]
nElo: 68.82 ±3.4
[raw statistics]
08/08/18 master vs Stockfish 9
Bench: 4669050
First check threshold in space evaluation
[differences] 207 		Elo: 37.78 ±1.9
[0-1]: [4224, 27220, 8556]
nElo: 67.82 ±3.4
[raw statistics]
12/08/18 master vs Stockfish 9
Bench: 4694813
Combo of several promising parameter tweaks
[differences] 211 		Elo: 40.88 ±1.9
[0-1]: [4069, 27177, 8754]
nElo: 73.46 ±3.4
[raw statistics]
14/08/18 master vs Stockfish 9
Bench: 4272361
Double weight of capture history
[differences] 214 		Elo: 41.69 ±1.9
[0-1]: [3942, 27339, 8719]
nElo: 75.47 ±3.4
[raw statistics]
17/08/18 master vs Stockfish 9
Bench: 4592766
Use an affine formula to mix stats and eval
[differences] 217 		Elo: 43.15 ±1.9
[0-1]: [3922, 27213, 8865]
nElo: 77.82 ±3.4
[raw statistics]
28/08/18 master vs Stockfish 9
Bench: 4172767
Tweak stat bonus formula
[differences] 220 		Elo: 44.20 ±1.9
[0-1]: [3861, 27217, 8922]
nElo: 79.79 ±3.4
[raw statistics]
28/08/18 master vs Stockfish 9
Bench: 4413173
Remove PawnsOnBothFlanks
[differences] 225 		Elo: 42.37 ±1.9
[0-1]: [3952, 27242, 8806]
nElo: 76.44 ±3.4
[raw statistics]
01/09/18 master vs Stockfish 9
Bench: 4609645
Re-introduce "keep pawns on both flanks"
[differences] 227 		Elo: 46.46 ±1.9
[0-1]: [3804, 27075, 9121]
nElo: 83.56 ±3.4
[raw statistics]
10/09/18 master vs Stockfish 9
Bench: 4248710
Tweak opposite colored bishops endgame scaling
[differences] 230 		Elo: 45.47 ±1.9
[0-1]: [3911, 26973, 9116]
nElo: 81.36 ±3.4
[raw statistics]
27/09/18 master vs Stockfish 9
Bench: 4059356
Fix two typos in comments
[differences] 235 		Elo: 46.93 ±1.9
[0-1]: [3883, 26864, 9253]
nElo: 83.72 ±3.4
[raw statistics]
14/10/18 master vs Stockfish 9
Bench: 4274207
Simplify check extensions
[differences] 241 		Elo: 49.01 ±1.9
[0-1]: [3783, 26829, 9388]
nElo: 87.49 ±3.4
[raw statistics]
25/10/18 master vs Stockfish 9
Bench: 3314347
On main thread: reduce depth after fail high
[differences] 245 		Elo: 52.82 ±1.9
[0-1]: [3514, 26937, 9549]
nElo: 95.10 ±3.4
[raw statistics]
01/11/18 master vs Stockfish 9
Bench: 3556672
Fix issues from using adjustedDepth too broadly
[differences] 248 		Elo: 51.68 ±1.9
[0-1]: [3581, 26932, 9487]
nElo: 92.90 ±3.4
[raw statistics]
08/11/18 master vs Stockfish 9
Bench: 3647775
Update list of top CPU contributors
[differences] 254 		Elo: 50.43 ±1.9
[0-1]: [3773, 26689, 9538]
nElo: 89.65 ±3.5
[raw statistics]
19/11/18 master vs Stockfish 9
Bench: 3717396
Stockfish 10-beta
[differences] 267 		Elo: 53.77 ±1.9
[0-1]: [3612, 26634, 9754]
nElo: 95.73 ±3.5
[raw statistics]
27/11/18 master vs Stockfish 9
Bench: 3939338
Simplify casting extension
[differences] 274 		Elo: 54.21 ±1.9
[0-1]: [3562, 26685, 9753]
nElo: 96.75 ±3.5
[raw statistics]
29/11/18 Stockfish 10 Stockfish Logo Chart
Bench: 3939338
Official Release
[differences] 277
Stockfish 11 Development (29/11/18 - 17/01/20)
Date Version 1 Thread 8 Threads
29/11/18 Stockfish 10 Stockfish Logo
Bench: 3939338
06/12/18 master vs Stockfish 10
Bench: 3773021
Revert "pseudo_legal() and MOVE_NONE"
[differences] 8 		Elo: 4.32 ±1.7
[0-1]: [5033, 29437, 5530]
nElo: 8.40 ±3.4
[raw statistics]
13/12/18 master vs Stockfish 10
Bench: 3332460
A combo of parameter tweaks
[differences] 16 		Elo: 8.06 ±1.8
[0-1]: [5020, 29032, 5948]
nElo: 15.41 ±3.4
[raw statistics] 		Elo: 12.70 ±1.7
[0-1]: [4068, 30403, 5529]
nElo: 25.98 ±3.4
[raw statistics]
16/12/18 master vs Stockfish 10
Bench: 3646542
Use stronglyProtected
[differences] 21 		Elo: 7.85 ±1.7
[0-1]: [5107, 30004, 6037]
nElo: 15.10 ±3.4
[raw statistics]
04/01/19 master vs Stockfish 10
Bench: 3559104
Check tablebase files
[differences] 40 		Elo: 7.20 ±1.8
[0-1]: [5164, 28843, 5993]
nElo: 13.64 ±3.4
[raw statistics]
10/01/19 master vs Stockfish 10
Bench: 3739723
Remove pvExact
[differences] 45 		Elo: 13.14 ±1.8
[0-1]: [4779, 28930, 6291]
nElo: 25.03 ±3.4
[raw statistics] 		Elo: 16.17 ±1.7
[0-1]: [3887, 30366, 5747]
nElo: 33.07 ±3.4
[raw statistics]
22/01/19 master vs Stockfish 10
Bench: 3665090
Simplify TrappedRook
[differences] 53 		Elo: 13.98 ±1.8
[0-1]: [4714, 28963, 6323]
nElo: 26.68 ±3.4
[raw statistics]
03/02/19 master vs Stockfish 10
Bench: 3653942
Less king danger if we have a knight
[differences] 61 		Elo: 17.71 ±1.8
[0-1]: [4624, 28715, 6661]
nElo: 33.46 ±3.4
[raw statistics] 		Elo: 19.77 ±1.7
[0-1]: [3728, 30270, 6002]
nElo: 40.32 ±3.4
[raw statistics]
12/03/19 master vs Stockfish 10
Bench: 3318033
Increase thread stack for OS X (#2035)
[differences] 80 		Elo: 16.58 ±1.8
[0-1]: [4635, 28823, 6542]
nElo: 31.46 ±3.4
[raw statistics]
31/03/19 master vs Stockfish 10
Bench: 3548313
Assorted trivial cleanups 3/2019 (#2030)
[differences] 91 		Elo: 16.58 ±1.8
[0-1]: [4742, 28609, 6649]
nElo: 31.16 ±3.4
[raw statistics] 		Elo: 24.33 ±1.7
[0-1]: [3633, 29937, 6430]
nElo: 48.91 ±3.4
[raw statistics]
24/04/19 master vs Stockfish 10
Bench: 3402947
Remove useless initializations (#2115)
[differences] 113 		Elo: 16.39 ±1.8
[0-1]: [4634, 28847, 6519]
nElo: 31.13 ±3.4
[raw statistics]
05/05/19 master vs Stockfish 10
Bench: 3644175
LMR for captures not cracking alpha
[differences] 121 		Elo: 16.65 ±1.8
[0-1]: [4788, 28508, 6704]
nElo: 31.17 ±3.4
[raw statistics]
15/05/19 master vs Stockfish 10
Bench: 3824325
Update failedHighCnt rule #2063
[differences] 136 		Elo: 19.76 ±1.8
[0-1]: [4665, 28397, 6938]
nElo: 36.86 ±3.4
[raw statistics] 		Elo: 28.93 ±1.7
[0-1]: [3573, 29531, 6896]
nElo: 57.18 ±3.4
[raw statistics]
09/06/19 master vs Stockfish 10
Bench: 3424592
Remove depth condition for ttPv (#2166)
[differences] 151 		Elo: 19.87 ±1.9
[0-1]: [4796, 28123, 7081]
nElo: 36.62 ±3.4
[raw statistics]
20/06/19 master vs Stockfish 10
Bench: 3398333
More bonus for free passed pawn
[differences] 161 		Elo: 24.06 ±1.8
[0-1]: [4547, 28140, 7313]
nElo: 44.48 ±3.4
[raw statistics] 		Elo: 30.76 ±1.7
[0-1]: [3462, 29544, 6994]
nElo: 60.92 ±3.4
[raw statistics]
27/06/19 master vs Stockfish 10
Bench: 3633546
Bonus for double attacks
[differences] 167 		Elo: 22.75 ±1.9
[0-1]: [4644, 28096, 7260]
nElo: 41.95 ±3.4
[raw statistics]
11/07/19 master vs Stockfish 10
Bench: 3206912
Assorted trivial cleanups June 2019
[differences] 176 		Elo: 24.39 ±1.9
[0-1]: [4596, 28005, 7399]
nElo: 44.83 ±3.4
[raw statistics]
25/07/19 master vs Stockfish 10
Bench: 3935523
Tweak of SEE pruning condition
[differences] 192 		Elo: 25.72 ±1.9
[0-1]: [4519, 28006, 7475]
nElo: 47.32 ±3.4
[raw statistics] 		Elo: 37.49 ±1.7
[0-1]: [3225, 29251, 7524]
nElo: 73.63 ±3.4
[raw statistics]
14/08/19 master vs Stockfish 10
Bench: 4139590
Tweak unsafe checks
[differences] 198 		Elo: 32.24 ±1.9
[0-1]: [4168, 27963, 7869]
nElo: 59.45 ±3.4
[raw statistics]
26/08/19 master vs Stockfish 10
Bench: 3568210
Tweak Late Move Reduction at root
[differences] 207 		Elo: 35.63 ±1.9
[0-1]: [4021, 27870, 8109]
nElo: 65.62 ±3.4
[raw statistics] 		Elo: 44.52 ±1.8
[0-1]: [2958, 28986, 8056]
nElo: 86.99 ±3.4
[raw statistics]
12/09/19 master vs Stockfish 10
Bench: 3954190
Scale down complexity
[differences] 211 		Elo: 39.10 ±1.9
[0-1]: [3824, 27869, 8307]
nElo: 72.22 ±3.4
[raw statistics]
16/09/19 master vs Stockfish 10
Bench: 4272173
Raise stack size to 8MB for pthreads
[differences] 218 		Elo: 37.63 ±1.9
[0-1]: [4007, 27670, 8323]
nElo: 68.83 ±3.4
[raw statistics] 		Elo: 46.57 ±1.8
[0-1]: [2764, 28492, 7994]
nElo: 91.44 ±3.4
[raw statistics]
24/09/19 master vs Stockfish 10
Bench: 3618154
Increase weight for supported pawns
[differences] 226 		Elo: 38.97 ±1.9
[0-1]: [3857, 27818, 8325]
nElo: 71.81 ±3.4
[raw statistics]
05/10/19 master vs Stockfish 10
Bench: 4131643
Introduce separate counter-move tables
[differences] 239 		Elo: 41.96 ±1.9
[0-1]: [3746, 27701, 8553]
nElo: 77.13 ±3.4
[raw statistics] 		Elo: 51.76 ±1.8
[0-1]: [2628, 28829, 8543]
nElo: 101.26 ±3.4
[raw statistics]
18/10/19 master vs Stockfish 10
Bench: 4423737
Current capture for Counter-Move history
[differences] 247 		Elo: 44.63 ±1.9
[0-1]: [3641, 27608, 8751]
nElo: 81.93 ±3.4
[raw statistics]
04/11/19 master vs Stockfish 10
Bench: 4707799
Rook PSQT Tuned
[differences] 259 		Elo: 42.20 ±1.9
[0-1]: [3686, 27793, 8521]
nElo: 77.91 ±3.4
[raw statistics] 		Elo: 52.90 ±1.8
[0-1]: [2601, 28754, 8645]
nElo: 103.29 ±3.4
[raw statistics]
14/11/19 master vs Stockfish 10
Bench: 4532366
Prune before extension
[differences] 266 		Elo: 43.12 ±1.9
[0-1]: [3676, 27709, 8615]
nElo: 79.39 ±3.4
[raw statistics]
21/11/19 master vs Stockfish 10
Bench: 5067870
Do lmr for more captures
[differences] 271 		Elo: 46.56 ±1.5
[0-1]: [5306, 41395, 13299]
nElo: 85.60 ±2.8
[raw statistics] 		Elo: 53.93 ±1.8
[0-1]: [2502, 28837, 8661]
nElo: 105.86 ±3.4
[raw statistics]
02/12/19 master vs Stockfish 10
Bench: 5122362
UnblockedStorm tuned
[differences] 278 		Elo: 44.88 ±1.5
[0-1]: [5273, 41746, 12981]
nElo: 83.21 ±2.8
[raw statistics]
10/12/19 master vs Stockfish 10
Bench: 5371271
Refine improving-logic
[differences] 288 		Elo: 47.27 ±1.5
[0-1]: [5329, 41229, 13442]
nElo: 86.56 ±2.8
[raw statistics] 		Elo: 56.62 ±1.8
[0-1]: [2365, 28809, 8826]
nElo: 111.42 ±3.4
[raw statistics]
07/01/20 master vs Stockfish 10
Bench: 4747984
Tuned nullmove search
[differences] 294 		Elo: 51.50 ±1.5
[0-2]: [160, 3173, 15729, 9546, 1387]
nElo: 98.05 ±2.8   PairsRatio: 3.28
[raw statistics] 		Elo: 58.15 ±1.7
[0-2]: [36, 1527, 11059, 6509, 860]
nElo: 118.69 ±3.4   PairsRatio: 4.71
[raw statistics]
17/01/20 master vs Stockfish 10
Bench: 5156767
Stockfish 11
[differences] 307 		Elo: 53.59 ±1.5
[0-2]: [138, 2988, 15833, 9631, 1407]
nElo: 102.99 ±2.8   PairsRatio: 3.53
[raw statistics] 		Elo: 58.07 ±1.7
[0-2]: [36, 1478, 11159, 6463, 854]
nElo: 119.25 ±3.4   PairsRatio: 4.83
[raw statistics]
17/01/20 Stockfish 11 Stockfish Logo Chart
Bench: 5156767
Official Release
[differences] 307
Stockfish 12 Development (17/01/20 - 02/09/20)
Date Version 1 Thread 8 Threads
17/01/20 Stockfish 11 Stockfish Logo
Bench: 5156767
28/01/20 master vs Stockfish 11
Bench: 5545845
More bonus for bestMoves
[differences] 16 		Elo: -2.47 ±1.3
[0-2]: [330, 5657, 18424, 5285, 303]
nElo: -5.21 ±2.8   PairsRatio: 0.93
[raw statistics]
31/01/20 master vs Stockfish 11
Bench: 5153165
Revert 5 recent patches
[differences] 19 		Elo: 0.85 ±1.3
[0-2]: [306, 5327, 18593, 5457, 314]
nElo: 1.80 ±2.8   PairsRatio: 1.02
[raw statistics]
27/02/20 master vs Stockfish 11
Bench: 4923286
Weak queen protection
[differences] 32 		Elo: 1.33 ±1.3
[0-2]: [327, 5308, 18486, 5567, 312]
nElo: 2.80 ±2.8   PairsRatio: 1.04
[raw statistics] 		Elo: 0.51 ±1.4
[0-2]: [118, 3072, 13560, 3133, 117]
nElo: 1.21 ±3.4   PairsRatio: 1.02
[raw statistics]
20/03/20 master vs Stockfish 11
Bench: 5398277
Adjust singular extension search depth
[differences] 48 		Elo: 2.94 ±1.3
[0-2]: [351, 5099, 18580, 5631, 339]
nElo: 6.21 ±2.8   PairsRatio: 1.10
[raw statistics]
07/04/20 master vs Stockfish 11
Bench: 4417023
Introduce capture history pruning
[differences] 63 		Elo: 5.74 ±1.3
[0-2]: [274, 5058, 18460, 5818, 390]
nElo: 12.11 ±2.8   PairsRatio: 1.16
[raw statistics] 		Elo: 6.49 ±1.5
[0-2]: [113, 2854, 13369, 3501, 163]
nElo: 15.05 ±3.4   PairsRatio: 1.23
[raw statistics]
16/04/20 master vs Stockfish 11
Bench: 4958027
Remove one condition in probcut TTmove
[differences] 76 		Elo: 11.33 ±1.3
[0-2]: [281, 4681, 18282, 6313, 443]
nElo: 23.65 ±2.8   PairsRatio: 1.36
[raw statistics]
02/05/20 master vs Stockfish 11
Bench: 4247490
Fishtest Tuning Framework
[differences] 84 		Elo: 15.21 ±1.3
[0-2]: [236, 4370, 18388, 6545, 461]
nElo: 32.08 ±2.8   PairsRatio: 1.52
[raw statistics] 		Elo: 16.71 ±1.5
[0-2]: [105, 2457, 13100, 4087, 251]
nElo: 37.85 ±3.4   PairsRatio: 1.69
[raw statistics]
21/05/20 master vs Stockfish 11
Bench: 4778956
Tweak knight mobility
[differences] 100 		Elo: 15.97 ±1.3
[0-2]: [230, 4544, 17963, 6766, 497]
nElo: 33.08 ±2.8   PairsRatio: 1.52
[raw statistics]
06/06/20 master vs Stockfish 11
Bench: 4582693
Use lowply-history also on low depths
[differences] 117 		Elo: 19.45 ±1.4
[0-2]: [250, 4360, 17761, 7042, 587]
nElo: 39.70 ±2.8   PairsRatio: 1.65
[raw statistics] 		Elo: 23.70 ±1.5
[0-2]: [88, 2142, 12987, 4524, 259]
nElo: 53.99 ±3.4   PairsRatio: 2.14
[raw statistics]
13/06/20 master vs Stockfish 11
Bench: 4246971
Tuned values for search constants
[differences] 127 		Elo: 20.91 ±1.4
[0-2]: [195, 4263, 17878, 7069, 595]
nElo: 43.14 ±2.8   PairsRatio: 1.72
[raw statistics] 		Elo: 24.86 ±1.5
[0-2]: [81, 2088, 13016, 4523, 292]
nElo: 56.58 ±3.4   PairsRatio: 2.22
[raw statistics]
29/06/20 master vs Stockfish 11
Bench: 4523573
Tweak single queen endgame scaling
[differences] 148 		Elo: 25.67 ±1.3
[0-2]: [192, 3878, 17888, 7397, 645]
nElo: 53.10 ±2.8   PairsRatio: 1.98
[raw statistics]
17/07/20 master vs Stockfish 11
Bench: 4578298
Do not overwrite valuable TT data
[differences] 163 		Elo: 26.44 ±1.3
[0-2]: [192, 3800, 17928, 7418, 662]
nElo: 54.75 ±2.8   PairsRatio: 2.02
[raw statistics] 		Elo: 30.71 ±1.5
[0-2]: [63, 1923, 12759, 4935, 320]
nElo: 69.50 ±3.4   PairsRatio: 2.65
[raw statistics]
31/07/20 master vs Stockfish 11
Bench: 4746616
Tweak cutnode reduction
[differences] 167 		Elo: 25.49 ±1.4
[0-2]: [203, 3910, 17861, 7342, 684]
nElo: 52.38 ±2.8   PairsRatio: 1.95
[raw statistics] 		Elo: 32.39 ±1.5
[0-2]: [69, 1829, 12779, 4961, 362]
nElo: 73.03 ±3.4   PairsRatio: 2.80
[raw statistics]
06/08/20 master vs Stockfish 11
Bench: 4746616
Add NNUE evaluation
[differences] 168 		Elo: 83.42 ±1.7
[0-2]: [172, 2656, 12724, 11761, 2687]
nElo: 144.72 ±3.0   PairsRatio: 5.11
[raw statistics] 		Elo: 86.10 ±1.9
[0-2]: [36, 1192, 9342, 7881, 1549]
nElo: 163.20 ±3.6   PairsRatio: 7.68
[raw statistics]
07/08/20 Add NNUE evaluation Stockfish Logo
Bench: 4746616
Official Release
[differences] 168
08/08/20 master vs Stockfish 11
Bench: 4084753
LMR search tweak
[differences] 185 		Elo: 106.20 ±1.7
[0-2]: [67, 1716, 11867, 13060, 3290]
nElo: 189.91 ±3.2   PairsRatio: 9.17
[raw statistics]
11/08/20 master vs Stockfish 11
Bench: 4290577
This commit enables a mixed bench
[differences] 205 		Elo: 125.60 ±1.7
[0-2]: [48, 1240, 10613, 14070, 4029]
nElo: 224.82 ±3.3   PairsRatio: 14.05
[raw statistics] 		Elo: 111.78 ±1.9
[0-2]: [11, 591, 8286, 9168, 1944]
nElo: 217.93 ±3.8   PairsRatio: 18.46
[raw statistics]
18/08/20 master vs Stockfish 11
Bench: 4026216
Fix Makefile typo
[differences] 226 		Elo: 121.54 ±1.7
[0-2]: [52, 1373, 10930, 13640, 4005]
nElo: 215.22 ±3.3   PairsRatio: 12.38
[raw statistics] 		Elo: 111.40 ±1.9
[0-2]: [20, 700, 8128, 9161, 1991]
nElo: 213.20 ±3.8   PairsRatio: 15.49
[raw statistics]
30/08/20 master vs Stockfish 11
Bench: 3736029
Update parameters in classical evaluation
[differences] 255 		Elo: 130.96 ±1.7
[0-2]: [44, 1161, 10305, 14128, 4362]
nElo: 232.58 ±3.4   PairsRatio: 15.34
[raw statistics]
02/09/20 master vs Stockfish 11
Bench: 3624569
Stockfish 12
[differences] 262 		Elo: 133.65 ±1.7
[0-2]: [32, 1088, 10158, 14286, 4436]
nElo: 238.67 ±3.4   PairsRatio: 16.72
[raw statistics] 		Elo: 117.62 ±1.9
[0-2]: [10, 562, 8016, 9195, 2217]
nElo: 224.93 ±3.8   PairsRatio: 19.95
[raw statistics]
02/09/20 Stockfish 12 Stockfish Logo Chart
Bench: 3624569
Official Release
[differences] 262
Stockfish 13 Development (02/09/20 - 18/02/21)
Date Version 1 Thread 8 Threads
02/09/20 Stockfish 12 Stockfish Logo
Bench: 3624569
08/09/20 master vs Stockfish 12
Bench: 4161067
Double probability of using classical eval
[differences] 10 		Elo: 6.49 ±1.0
[0-2]: [85, 3319, 22112, 4359, 125]
nElo: 17.26 ±2.8   PairsRatio: 1.32
[raw statistics]
21/09/20 master vs Stockfish 12
Bench: 3973739
Add large page support for NNUE weights
[differences] 21 		Elo: 13.88 ±1.0
[0-2]: [49, 2767, 22106, 4896, 182]
nElo: 37.07 ±2.8   PairsRatio: 1.80
[raw statistics] 		Elo: 8.97 ±1.1
[0-2]: [15, 1474, 16020, 2445, 46]
nElo: 27.99 ±3.4   PairsRatio: 1.67
[raw statistics]
28/09/20 master vs Stockfish 12
Bench: 3776081
Include pawns in NNUE scaling
[differences] 33 		Elo: 23.15 ±1.0
[0-2]: [38, 1945, 22217, 5587, 213]
nElo: 63.29 ±2.7   PairsRatio: 2.92
[raw statistics]
18/10/20 master vs Stockfish 12
Bench: 4066972
Do more reductions for late quiet moves
[differences] 41 		Elo: 24.09 ±1.0
[0-2]: [43, 2023, 21889, 5827, 218]
nElo: 64.60 ±2.7   PairsRatio: 2.93
[raw statistics] 		Elo: 21.17 ±1.1
[0-2]: [12, 908, 15789, 3216, 75]
nElo: 65.43 ±3.2   PairsRatio: 3.58
[raw statistics]
01/11/20 master vs Stockfish 12
Bench: 3517795
Update default net to nn-cb26f10b1fd9.nnue
[differences] 48 		Elo: 28.02 ±1.1
[0-2]: [63, 2079, 21107, 6469, 282]
nElo: 71.59 ±2.7   PairsRatio: 3.15
[raw statistics]
15/11/20 master vs Stockfish 12
Bench: 3597730
Rook Mobility Tweak
[differences] 60 		Elo: 29.99 ±1.0
[0-2]: [32, 1667, 21658, 6389, 254]
nElo: 80.38 ±2.7   PairsRatio: 3.91
[raw statistics] 		Elo: 25.49 ±1.1
[0-2]: [10, 799, 15532, 3570, 89]
nElo: 77.27 ±3.2   PairsRatio: 4.52
[raw statistics]
29/11/20 master vs Stockfish 12
Bench: 3561701
Update default net to nn-62ef826d1a6d.nnue
[differences] 72 		Elo: 30.61 ±1.0
[0-2]: [19, 1645, 21655, 6407, 274]
nElo: 82.09 ±2.7   PairsRatio: 4.02
[raw statistics]
14/12/20 master vs Stockfish 12
Bench: 4050630
Increase reduction in case of stable best move
[differences] 79 		Elo: 32.09 ±1.0
[0-2]: [33, 1581, 21474, 6651, 261]
nElo: 85.57 ±2.7   PairsRatio: 4.28
[raw statistics] 		Elo: 27.50 ±1.1
[0-2]: [10, 706, 15480, 3723, 81]
nElo: 83.75 ±3.1   PairsRatio: 5.31
[raw statistics]
31/12/20 master vs Stockfish 12
Bench: 4109336
WeakUnopposed penalty for backwards
[differences] 89 		Elo: 33.71 ±1.0
[0-2]: [23, 1475, 21475, 6730, 297]
nElo: 90.01 ±2.6   PairsRatio: 4.69
[raw statistics]
13/01/21 master vs Stockfish 12
Bench: 4287509
Optimize generate_moves
[differences] 101 		Elo: 32.40 ±1.0
[0-2]: [31, 1487, 21588, 6660, 234]
nElo: 87.55 ±2.7   PairsRatio: 4.54
[raw statistics] 		Elo: 28.29 ±1.1
[0-2]: [10, 671, 15468, 3761, 90]
nElo: 86.06 ±3.1   PairsRatio: 5.65
[raw statistics]
15/02/21 master vs Stockfish 12
Bench: 3766422
Small trivial clean-ups, February 2021
[differences] 121 		Elo: 36.03 ±1.1
[0-2]: [29, 1395, 21210, 7079, 287]
nElo: 95.63 ±2.7   PairsRatio: 5.17
[raw statistics] 		Elo: 29.08 ±1.1
[0-2]: [6, 626, 15476, 3806, 86]
nElo: 89.08 ±3.1   PairsRatio: 6.16
[raw statistics]
18/02/21 Stockfish 13 Stockfish Logo Chart
Bench: 3766422
Official Release
[differences] 123
Stockfish 14 Development (18/02/21 - 02/07/21)
Date Version 1 Thread 8 Threads
18/02/21 Stockfish 13 Stockfish Logo
Bench: 3766422
26/02/21 master vs Stockfish 13
Bench: 5037279
Introduce DistanceFromPV
[differences] 4 		Elo: 1.34 ±0.8
[0-2]: [28, 2367, 24980, 2596, 29]
nElo: 4.55 ±2.8   PairsRatio: 1.10
[raw statistics]
24/03/21 master vs Stockfish 13
Bench: 4339126
Small cleanups (march 2021)
[differences] 18 		Elo: 0.61 ±0.8
[0-2]: [18, 2457, 24938, 2575, 12]
nElo: 2.09 ±2.8   PairsRatio: 1.05
[raw statistics]
15/04/21 master vs Stockfish 13
Bench: 4503918
Use classical eval for Bishop vs Pawns
[differences] 29 		Elo: 1.47 ±0.8
[0-2]: [39, 2384, 24886, 2667, 24]
nElo: 4.93 ±2.8   PairsRatio: 1.11
[raw statistics] 		Elo: 0.89 ±0.9
[0-2]: [11, 1279, 17318, 1381, 11]
nElo: 3.38 ±3.4   PairsRatio: 1.08
[raw statistics]
22/05/21 master vs Stockfish 13
Bench: 3856635
Sometimes change the balance
[differences] 62 		Elo: 10.12 ±1.0
[0-2]: [60, 2454, 23277, 4096, 113]
nElo: 29.34 ±2.8   PairsRatio: 1.67
[raw statistics]
14/06/21 master vs Stockfish 13
Bench: 4877339
Update default net to nn-8e47cf062333.nnue
[differences] 90 		Elo: 21.80 ±1.1
[0-2]: [67, 2216, 21852, 5620, 245]
nElo: 57.47 ±2.7   PairsRatio: 2.57
[raw statistics] 		Elo: 16.96 ±1.1
[0-2]: [15, 1083, 15923, 2894, 85]
nElo: 52.38 ±3.3   PairsRatio: 2.71
[raw statistics]
18/06/21 master vs Stockfish 13
Bench: 4900906
Make net nn-50144f835024.nnue the default
[differences] 100 		Elo: 25.56 ±1.0
[0-2]: [30, 1814, 22084, 5864, 208]
nElo: 69.95 ±2.7   PairsRatio: 3.29
[raw statistics]
29/06/21 master vs Stockfish 13
Bench: 4770936
Update Top CPU Contributors
[differences] 113 		Elo: 30.27 ±1.0
[0-2]: [14, 1443, 22127, 6146, 270]
nElo: 83.66 ±2.6   PairsRatio: 4.40
[raw statistics] 		Elo: 22.62 ±1.1
[0-2]: [7, 755, 15977, 3153, 108]
nElo: 71.15 ±3.1   PairsRatio: 4.28
[raw statistics]
02/07/21 Stockfish 14 Stockfish Logo Chart
Bench: 4770936
Official Release
[differences] 114
Stockfish 15 Development (02/07/21 - 18/04/22)
Date Version 1 Thread 8 Threads
02/07/21 Stockfish 14 Stockfish Logo
Bench: 4770936
26/07/21 master vs Stockfish 14
Bench: 5124774
Update default net to nn-26abeed38351.nnue
[differences] 17 		Elo: 2.74 ±0.8
[0-2]: [24, 2000, 25476, 2478, 22]
nElo: 9.85 ±2.8   PairsRatio: 1.24
[raw statistics]
15/08/21 master vs Stockfish 14
Bench: 5189338
New NNUE architecture and net
[differences] 26 		Elo: 9.31 ±0.9
[0-2]: [24, 2044, 24321, 3522, 89]
nElo: 29.61 ±2.7   PairsRatio: 1.75
[raw statistics] 		Elo: 6.08 ±0.9
[0-2]: [5, 1063, 17183, 1725, 24]
nElo: 22.66 ±3.4   PairsRatio: 1.64
[raw statistics]
31/08/21 master vs Stockfish 14
Bench: 5600615
Update default net to nn-735bba95dec0.nnue
[differences] 39 		Elo: 15.04 ±0.9
[0-2]: [17, 1601, 24272, 3990, 120]
nElo: 47.86 ±2.7   PairsRatio: 2.54
[raw statistics]
15/09/21 master vs Stockfish 14
Bench: 6658747
Update default net to nn-13406b1dcbe0.nnue
[differences] 46 		Elo: 16.64 ±0.9
[0-2]: [21, 1878, 23452, 4506, 143]
nElo: 49.53 ±2.7   PairsRatio: 2.45
[raw statistics] 		Elo: 12.39 ±0.9
[0-2]: [1, 766, 17084, 2104, 45]
nElo: 45.59 ±3.2   PairsRatio: 2.80
[raw statistics]
06/10/21 master vs Stockfish 14
Bench: 6261865
Capping stat bonus at 2000
[differences] 57 		Elo: 18.68 ±0.9
[0-2]: [28, 1496, 23821, 4535, 120]
nElo: 57.70 ±2.7   PairsRatio: 3.05
[raw statistics] 		Elo: 11.74 ±0.9
[0-2]: [4, 769, 17137, 2052, 38]
nElo: 43.60 ±3.2   PairsRatio: 2.70
[raw statistics]
18/10/21 master vs Stockfish 14
Bench: 5005810
Simplify probCutCount away
[differences] 67 		Elo: 17.69 ±0.9
[0-2]: [13, 1577, 23891, 4382, 137]
nElo: 54.78 ±2.7   PairsRatio: 2.84
[raw statistics]
23/10/21 master vs Stockfish 14
Bench: 6334068
Adjust ButterflyHistory decay parameter
[differences] 78 		Elo: 17.87 ±0.9
[0-2]: [11, 1377, 24244, 4253, 115]
nElo: 57.35 ±2.6   PairsRatio: 3.15
[raw statistics] 		Elo: 10.27 ±0.9
[0-2]: [3, 696, 17438, 1842, 21]
nElo: 40.55 ±3.2   PairsRatio: 2.67
[raw statistics]
28/10/21 Stockfish 14.1 Stockfish Logo
Bench: 6334068
Official Release
[differences] 80
05/11/21 master vs Stockfish 14
Bench: 6719976
Tweak initial aspiration window
[differences] 89 		Elo: 18.71 ±0.9
[0-2]: [16, 1293, 24255, 4319, 117]
nElo: 60.14 ±2.6   PairsRatio: 3.39
[raw statistics]
23/11/21 master vs Stockfish 14
Bench: 7334766
Less futility pruning
[differences] 98 		Elo: 19.35 ±0.9
[0-2]: [19, 1405, 23923, 4524, 129]
nElo: 60.39 ±2.6   PairsRatio: 3.27
[raw statistics] 		Elo: 13.28 ±0.9
[0-2]: [3, 696, 17112, 2148, 41]
nElo: 49.26 ±3.2   PairsRatio: 3.13
[raw statistics]
28/11/21 master vs Stockfish 14
Bench: 6302543
Refine futility pruning for parent nodes
[differences] 103 		Elo: 24.44 ±0.9
[0-2]: [9, 1054, 23776, 5037, 124]
nElo: 76.95 ±2.5   PairsRatio: 4.86
[raw statistics]
07/12/21 master vs Stockfish 14
Bench: 4667742
Update default net to nn-63376713ba63.nnue
[differences] 118 		Elo: 26.99 ±0.9
[0-2]: [11, 998, 23473, 5365, 153]
nElo: 83.13 ±2.5   PairsRatio: 5.47
[raw statistics] 		Elo: 17.80 ±0.9
[0-2]: [6, 529, 16919, 2504, 42]
nElo: 64.76 ±3.1   PairsRatio: 4.76
[raw statistics]
14/12/21 master vs Stockfish 14
Bench: 4735679
Remove NNUE scaling term
[differences] 126 		Elo: 26.45 ±0.9
[0-2]: [9, 962, 23656, 5207, 166]
nElo: 82.28 ±2.5   PairsRatio: 5.53
[raw statistics]
22/12/21 master vs Stockfish 14
Bench: 4633875
Update default net to nn-ac07bd334b62.nnue
[differences] 139 		Elo: 28.65 ±0.9
[0-2]: [11, 1036, 23172, 5567, 214]
nElo: 85.61 ±2.5   PairsRatio: 5.52
[raw statistics] 		Elo: 17.66 ±0.9
[0-2]: [2, 520, 16976, 2448, 54]
nElo: 64.60 ±3.0   PairsRatio: 4.79
[raw statistics]
10/01/22 master vs Stockfish 14
Bench: 4572746
Adjust pruning constants
[differences] 148 		Elo: 30.51 ±1.0
[0-2]: [13, 1065, 22809, 5879, 234]
nElo: 89.03 ±2.5   PairsRatio: 5.67
[raw statistics]
29/01/22 master vs Stockfish 14
Bench: 4637392
Do stats updates after LMR for captures
[differences] 159 		Elo: 32.07 ±1.0
[0-2]: [10, 1009, 22681, 6049, 251]
nElo: 93.05 ±2.5   PairsRatio: 6.18
[raw statistics] 		Elo: 22.31 ±1.0
[0-2]: [3, 496, 16495, 2945, 61]
nElo: 76.78 ±3.0   PairsRatio: 6.02
[raw statistics]
10/02/22 master vs Stockfish 14
Bench: 4919707
Update architecture to "SFNNv4"
[differences] 166 		Elo: 34.88 ±1.0
[0-2]: [13, 884, 22430, 6432, 241]
nElo: 100.85 ±2.5   PairsRatio: 7.44
[raw statistics] 		Elo: 24.37 ±1.0
[0-2]: [2, 416, 16441, 3061, 80]
nElo: 83.29 ±2.9   PairsRatio: 7.51
[raw statistics]
17/02/22 master vs Stockfish 14
Bench: 6318903
Tune search at very long time control
[differences] 168 		Elo: 33.07 ±1.0
[0-2]: [17, 984, 22522, 6243, 234]
nElo: 95.49 ±2.5   PairsRatio: 6.47
[raw statistics] 		Elo: 23.83 ±1.0
[0-2]: [4, 410, 16496, 3023, 67]
nElo: 82.31 ±2.9   PairsRatio: 7.46
[raw statistics]
19/03/22 master vs Stockfish 14
Bench: 7044203
Remove ttPv tree shrinking
[differences] 180 		Elo: 35.01 ±1.0
[0-2]: [11, 801, 22566, 6395, 227]
nElo: 102.62 ±2.5   PairsRatio: 8.16
[raw statistics]
17/04/22 master vs Stockfish 14
Bench: 8129754
Decrease LMR at PV nodes with low depth
[differences] 189 		Elo: 36.69 ±1.0
[0-2]: [5, 711, 22489, 6557, 238]
nElo: 107.69 ±2.4   PairsRatio: 9.49
[raw statistics] 		Elo: 26.09 ±1.0
[0-2]: [1, 341, 16379, 3217, 62]
nElo: 89.84 ±2.8   PairsRatio: 9.59
[raw statistics]
18/04/22 Stockfish 15 Stockfish Logo Chart
Bench: 8129754
Official Release
[differences] 190

External Links

There are several pages on the web run by chess engine fans. Some collect progress of Stockfish over previous stable versions and development builds. Some compare Stockfish progress to other chess engines. Here is a collection of some useful links in that regard.

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