Stockfish

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Stockfish, an UCI compatible open source chess engine developed by Tord Romstad, Marco Costalba, Joona Kiiski and Gary Linscott, licensed under the GPL v3.0. Marco forked the project from version 2.1 of Tord's engine Glaurung, first announced by Marco in November 8, 2008, and in early 2009 Joona's Smaug, a further Glaurung 2.2 derivative, was incorporated. Starting out among the top twenty engines, Stockfish has quickly climbed in strength to become the world strongest chess entity as of 2018 - at least concerning the AlphaZero hype, public available chess entity. The name "Stockfish" reflects the ancestry of the engine. Tord is Norwegian and Marco Italian, and there is a long history of stockfish trade from Norway to Italy (to Marco's home town of Vicenza, in fact). Stockfish also referred another famous "little fish", the then strongest chess engine Rybka. In 2011, Marco Costalba and Joona Kiiski stepped down as Stockfish maintainers. From that, the project is being developed and maintained by the Stockfish community.

A synergy effect with the Shogi community led to the promising branch of Stockfish NNUE, courtesy of Nodchip, who introduced NNUE to Stockfish in 2019. On September 02, 2020, Stockfish 12 was released with a huge jump in playing strength due to NNUE and further tuning of the engine. The release of Stockfish 13 on February 19, 2021, has been triggered by the start of sales of the Fat Fritz 2 engine by ChessBase, based on a recent development version of Stockfish with minor modifications. Stockfish 14, released on July 02, 2021, further improved due to efforts by Tomasz Sobczyk and Gary Linscott in designing a new NNUE architecture in conjunction with a GPU accelerated trainer written in PyTorch. Further, the collaboration with the Leela Chess Zero team payed off, in providing billions of positions to train the new NNUE.

=Science versus Commerce?= There is a wide range of opinions about strong open source chess engines affecting commercial and competitive interests, as well as monetary interests from computer chess users, who obtain a top engine for free. The scientific and social value of strong open-source programs is indisputable. The teamwork effort to share ideas and knowledge to write one of the strongest programs, which everybody may follow and share to learn and play for free, is definitely a challenging and motivating task, gathering both admiration and enviousness. Obviously, professional programmers of commercial chess programs are not that enthusiastic about the development and need to improve further and/or focus more on secondary features or other business concepts like online play and/or user interface issues rather than on pure playing strength.

Also, many hobbyist chess programmers feel in the antagonism as well, not only caused by Stockfish with its highly respected authors, and before by Fruit and slightly Crafty, but from Ippolit and all its successors by pseudonymous authors and disputed origin. The implications on commercial and competitive computer chess are not quite clear, but presumably, the decrease in the number of participants of over the board tournaments will progress and clone suspicions may float like a Sword of Damocles over the scene, whether programmers took ideas too literally or not.

=Platforms= Since Stockfish is written in C++, it may be compiled and build for various processors and operating systems such as Android, iOS, Linux, macOS, and Windows. Stockfish for macOS was built by Daylen Yang, who is also responsible for the Stockfish website. Stockfish for iOS was built by Tord Romstad.

=Fishtest= The Stockfish Testing Framework dubbed Fishtest is a web application written by Gary Linscott, based on a SETI@home kind of volunteer computing. Fishtest is mainly written in Python under the Pyramid Application Development Framework, and distributes games across different machines to reduce the test latency and increment throughput. Started in early 2013 with Stockfish 3.0, Fishtest has hundreds of contributors, as of June 2018, 1130 testers and 162 developers active in testing ideas and tweaks, to make Stockfish the strongest chess entity of the world. =Evaluation Guide= Since April 2017 the interactive Stockfish Evaluation Guide is available to explore Stockfish's evaluation with a JavaScript implementation running in a browser. One may enter a FEN string of a position, to get the resulting score of the main evaluation term considering the game phases within its tapered evaluation, and may navigate through the tree of subterms and features with its particular characteristics for the given position.

=Tournament Play= Stockfish is top contender of the prestigious Top Chess Engines Competition (TCEC), reaching the superfinals since season 4, and established its world number one status in winning TCECs, leaving its commercial rivals Komodo and Houdini behind. Since season 14 in early 2019, Stockfish competes with the deep learning Leela Chess Zero engines, whose playing strength triggered a motivation boost in the developing community to further improve Stockfish. =GM+Rybka vs. Stockfish= On July 19, 2014, Stockfish 5 played a four game match versus Daniel Naroditsky plus Rybka 3 (2008), 45 minutes plus 30-second increment. Stockfish won 3½ - ½. A few weeks later the experiment continued with Hikaru Nakamura in Burlingame, California. Supported two games by Rybka 3, Nakamura lost ½ - 1½, two games with pawn odds (Stockfish both Black without h- and b-pawn) ended ½ - 1½ in favour to Stockfish 5 as well. It played the latest development build compiled for OS X running on a 3 GHz 8-Core Mac Pro.

=Selected Features=

Board Representation

 * Bitboards with Little-Endian Rank-File Mapping (LERF)
 * Magic Bitboards
 * BMI2 - PEXT Bitboards (not recommend for AMD Ryzen prior to Zen 3)


 * Piece-Lists

Search

 * Iterative Deepening
 * Aspiration Windows
 * Parallel Search using Threads
 * YBWC prior to Stockfish 7
 * Lazy SMP since Stockfish 7, January 2016
 * Principal Variation Search
 * Transposition Table
 * Shared Hash Table
 * 10 Bytes per Entry, 3 Entries per Cluster
 * Depth-preferred Replacement Strategy
 * No PV-Node probing
 * Prefetch
 * Move Ordering
 * Countermove Heuristic
 * Counter Moves History since Stockfish 7, January 2016
 * History Heuristic
 * Internal Iterative Deepening
 * Killer Heuristic
 * MVV/LVA
 * SEE
 * Selectivity
 * Extensions
 * Check Extensions if SEE >= 0
 * Restricted Singular Extensions
 * Pruning
 * Futility Pruning
 * Move Count Based Pruning
 * Null Move Pruning
 * Dynamic Depth Reduction based on depth and value
 * Static Null Move Pruning
 * Verification search at high depths
 * ProbCut
 * SEE Pruning
 * Reductions
 * Late Move Reductions
 * Razoring
 * Quiescence Search

Evaluation

 * NNUE
 * HalfKP (Strockfish 12)
 * HalfKAv2 (Strockfish 14)
 * See also Evaluation Philosophy


 * Tapered Eval
 * Score Grain: ~1/256 of a pawn unit
 * Material
 * Point Values
 * Midgame: 198, 817, 836, 1270, 2521
 * Endgame: 258, 846, 857, 1278, 2558
 * Bishop Pair
 * Imbalance Tables
 * Material Hash Table
 * Piece-Square Tables
 * Space
 * Mobility
 * Trapped Pieces
 * Rooks on (Semi) Open Files
 * Outposts
 * Pawn Structure
 * Pawn Hash Table
 * Backward Pawn
 * Doubled Pawn
 * Isolated Pawn
 * Phalanx
 * Connected Pawns
 * Passed Pawn
 * King Safety
 * Attacking King Zone
 * Pawn Shelter
 * Pawn Storm
 * Square Control
 * Evaluation Patterns

Misc

 * Chess960
 * Stockfish's Tuning Method
 * SPSA


 * Syzygy Bases

=Release Dates=

2008

 * Stockfish 1.0 - November 02, 2008
 * Stockfish 1.01 - November 03, 2008
 * Stockfish 1.1 - December 06, 2008
 * Stockfish 1.1a - December 08, 2008
 * Stockfish 1.2 - December 29, 2008

2009

 * Stockfish 1.3 - May 02, 2009
 * Stockfish 1.3.1 - May 03, 2009
 * Stockfish 1.4 - July 05, 2009
 * Stockfish 1.5 - October 04, 2009
 * Stockfish 1.5.1 - October 11, 2009
 * Stockfish 1.6 - December 25, 2009
 * Stockfish 1.6.1 - December 25, 2009
 * Stockfish 1.6.2 - December 31, 2009

2010 ...
2011 2012 2013
 * Stockfish 1.6.3 - February 02, 2010
 * Stockfish 1.7 - April 08, 2010
 * Stockfish 1.7.1 - April 10, 2010
 * Stockfish 1.8 - July 02, 2010
 * Stockfish 1.9 - October 02, 2010
 * Stockfish 1.9.1 - October 05, 2010
 * Stockfish 2.0 - January 01, 2011
 * Stockfish 2.0.1 - January 04, 2011
 * Stockfish 2.1 - May 04, 2011
 * Stockfish 2.1.1 - May 08, 2011
 * Stockfish 2.2 - December 29, 2011
 * Stockfish 2.2.1 - January 06, 2012
 * Stockfish 2.2.2 - January 14, 2012
 * Stockfish 2.3 - September 15, 2012
 * Stockfish 2.3.1 - September 22, 2012
 * Stockfish 3 - April 30, 2013
 * Stockfish 4 - August 20, 2013
 * Stockfish DD - November 29, 2013
 * Stockfish 5 - May 31, 2014

2015 ...

 * Stockfish 6 - January 27, 2015
 * Stockfish 7 - January 02, 2016
 * Stockfish 8 - November 01, 2016
 * Stockfish 9 - February 01, 2018
 * Stockfish 10 - November 29, 2018

2020 ...
=Ports= =Derivatives=
 * Stockfish 11 - January 18, 2020
 * Stockfish 12 - September 02, 2020
 * Stockfish 13 - February 19, 2021
 * Stockfish 14 - July 02, 2021
 * asmFish
 * CFish
 * DroidFish
 * Portfish
 * Rustfish
 * Stockfish-js
 * Brainfish
 * Crystal
 * DON
 * Eman
 * Fat Fritz 2.0
 * Houdini
 * McBrain
 * ShashChess
 * Sting
 * SugaR

=Authors=
 * Marco Costalba
 * Joona Kiiski
 * Gary Linscott
 * Tord Romstad
 * Contributors

=Elo Progress= of Stockfish in first 10 years

=See also=
 * Evaluation Philosophy
 * Glaurung
 * Leela Chess Zero
 * Raspberry Turk
 * NNUE
 * Stockfish NNUE
 * HalfKP (Strockfish 12)
 * HalfKAv2 (Strockfish 14)

=Publications=
 * Arno Nickel (2012). Die schöne neue Welt der Schachengines. SCHACH 2,3,5,6 2012, pdf (German)
 * Oleg Arenz (2012). Monte Carlo Chess. B.Sc. thesis, Darmstadt University of Technology, advisor Johannes Fürnkranz, pdf » Monte-Carlo Tree Search
 * Tamal T. Biswas, Kenneth W. Regan (2015). Quantifying Depth and Complexity of Thinking and Knowledge. ICAART 2015, pdf
 * Tamal T. Biswas, Kenneth W. Regan (2015). Measuring Level-K Reasoning, Satisficing, and Human Error in Game-Play Data. IEEE ICMLA 2015, pdf preprint
 * Shu Yokoyama, Tomoyuki Kaneko, Tetsuro Tanaka (2015). Parameter-Free Tree Style Pipeline in Asynchronous Parallel Game-Tree Search. Advances in Computer Games 14, pdf » P-GPP
 * Jean-Marc Alliot (2017). Who is the Master? ICGA Journal, Vol. 39, No. 1, draft as pdf

=Forum Posts=

2008 ...
2009
 * Stockfish 1.0 by Marco Costalba, CCC, November 02, 2008
 * Please drop Stockfish by Marco Costalba, CCC, November 07, 2008
 * Re: Stockfish - Glaurung by Tord Romstad, WBEC-Ridderkerk forum, September 05, 2009
 * Stockfish 1.5.1 by Marco Costalba, CCC, October 08, 2009

2010 ...
2011 2012 2013 2014
 * Stockfish 1.7 by Marco Costalba, CCC, April 08, 2010
 * Stockfish-1.7.0 Hyper-threading Detection by Louis Zulli, CCC, April 09, 2010 » Thread
 * stockfish fail high fail low by Uri Blass, CCC, April 13, 2010
 * MTD experiment with stockfish 1.7.1 by Vratko Polák, CCC, April 15, 2010
 * about stockfish and logic by Uri Blass, CCC, April 17, 2010
 * Stockfish - material balance/imbalance evaluation by Ralph Stoesser, CCC, May 05, 2010
 * Qsearch of Stockfish 1.7.1 by Ferdinand Mosca, CCC, May 13, 2010
 * Stockfish do_move + undo_move by Matthew Purland, CCC, June 02, 2010
 * static null move pruning is stockfish by Tom King, CCC, June 13, 2010
 * Stockfish - single evasion extensions by Ralph Stoesser, CCC, June 27, 2010
 * Stockfish 1.8 JA available by Jim Ablett, CCC, July 02, 2010
 * stockfish 1.8 - Eval hash gone? by Edward Yu, CCC, July 04, 2010
 * Stockfish Singular Extension, does it make sense? by Volker Böhm, CCC, July 08, 2010
 * Stockfish 1.8 tweaks by Vratko Polák, CCC, July 09, 2010
 * Stockfish question by Rebel, OpenChess Programming Forum, July 10, 2010
 * Taken from CCC (Stockfish & mainlines) by Rebel, OpenChess Programming Forum, July 12, 2010
 * backward pawns in Stockfish by Marek Kwiatkowski, CCC, July 16, 2010
 * Questions for the Stockfish team by Michael Sherwin, CCC, July 16, 2010
 * Stockfish 1.8 - eval cache by Ralph Stoesser, CCC, July 18, 2010 » Evaluation Hash Table
 * Stockfish null move pre-condition by Rein Halbersma, CCC, July 22, 2010 » Null Move Pruning
 * Stockfish for 39 dollars by Matthias Gemuh, CCC, August 26, 2010
 * Stockfish 1.9 JA update available by Jim Ablett, CCC, October 02, 2010
 * mobility evaluation of stockfish by Uri Blass, CCC, October 09, 2010
 * Stockfish 2.0 Available by Jim Ablett, CCC, January 01, 2011
 * Stockfish 2.0.0 tests by Harun Taner, CCC, January 04, 2011
 * Stockfish "Use Sleeping Threads" Test by Louis Zulli, CCC, January 05, 2011
 * StockFish engine by Andriy Dzyben, CCC, January 11, 2011
 * Designing an analysis friendly Stockfish? by Uly, Open Chess Programming Forum, January 28, 2011
 * Why are the Ippo derivative stronger than Stockfish? by Larry Kaufman, CCC, 24 February, 2011
 * Transposition Table updates in Stockfish by Onno Garms, CCC, April 12, 2011 » Transposition Table
 * Stockfish random generator (rkiss.h) by Martin Sedlak, CCC, Apr 15, 2011 » Bob Jenkins
 * futility pruning in stockfish by Engin Üstün, CCC, May 25, 2011 » Futility Pruning
 * Stockfish clones in the AppStore: it's becoming a plague... by Julien Marcel, CCC, May 28, 2011 » Clones
 * Root node search in Stockfish by Onno Garms, CCC, June 12, 2011 » Move Ordering, Root
 * Grandmaster prefers Stockfish evals by Albert Silver, CCC, September 29, 2011
 * Stockfish on github by Marco Costalba, CCC, October 02, 2011
 * Stockfish's tuning method by Joona Kiiski, CCC, October 07, 2011 » Stockfish's Tuning Method
 * StockFish LS with LimitStrength feature by Alexander Schmidt, CCC, January 01, 2012
 * Stockfish Code ( Piece Value's) by Nolan Denson, CCC, January 10, 2012 » Point Value
 * Stockfish hash implementation by Jon Dart, CCC, January 10, 2012 » Transposition Table
 * Stockfish 2.2.2 JA update available by Jim Ablett, CCC, January 14, 2012
 * CLOP on Stockfish by Gary, CCC, March 10, 2012 » CLOP
 * optimal aspiration window for stockfish question by Uri Blass, CCC, March 12, 2012 » Aspiration Windows
 * Raspberry Pi / Stockfish dedicated chess computer/board by Jean-Francois Romang, CCC, August 26, 2012 » Raspberry Pi, Dedicated Chess Computers
 * Stockfish 2.3 update available by Jim Ablett, CCC, September 15, 2012
 * 10 Lessons to be Learned from todays Top Engines by Josef, Rybka Forum, January 03, 2013 » Houdini, Komodo
 * Stockfish 3 Official JA Windows/Linux builds available by Jim Ablett, CCC, April 30, 2013
 * Fishtest Distributed Testing Framework by Marco Costalba, CCC, May 01, 2013 » Fishtest
 * Re: History pruning / move ordering question by Joona Kiiski, CCC, May 12, 2013 » Countermove Heuristic
 * Stockfish 3 PA_GTB by Jeremy Bernstein, OpenChess Forum, May 15, 2013
 * Probcut by Gary, CCC, May 24, 2013 » ProbCut
 * Stockfish bug by Steven Atkinson, CCC, May 30, 2013 » Repetitions
 * The Ultimate Stockfish! by Mike Scheidl, CCC, July 09, 2013
 * use sleeping threads by Don Dailey, CCC, July 10, 2013 » Parallel Search, Thread
 * Stockfish 4 by Marco Costalba, CCC, August 20, 2013
 * 18 days from SF4 release and about ~30+ ELO gain! by Alexandre Meirelles Souza, CCC, September 08, 2013
 * How much of Stockfish code is still from Tord Romstad? by Jouni Uski, CCC, September 16, 2013
 * Syzygy tablebases, work in Stockfish? by Jose Mº Velasco, CCC, September 23, 2013 » Syzygy Bases
 * Stockfish search by Harm Geert Muller, CCC, October 28, 2013 » Principal Variation
 * Some food for thought by Spacious Mind, Hiarcs Forum, November 11, 2013 » Stockfish vs. Tasc CM32 512K The King 2.2
 * Stockfish scaling by Ed Schröder, CCC, November 15, 2013
 * Stockfish depth vs. others; challenge by Larry Kaufman, CCC, November 24, 2013 » Depth
 * Stockfish DD: a new official release by Marco Costalba, CCC, November 29, 2013 » TCEC Season 5, dedicated to Don Dailey
 * Stockfish Syzygy: how to interpret mates? by Jouni Uski, CCC, December 01, 2013 » Syzygy Bases, Mate Scores
 * Is SF DD greater efficiency would be null move pruning? by Jonathan Lee, CCC, December 22, 2013 » Null Move Pruning
 * Help me to test an idea for Stockfish by Robert Tournevisse, CCC, January 03, 2014 » Piece-Square Tables, Tapered Eval
 * Stockfish seems definitely the strongest engine by Kai Laskos, CCC, January 21, 2014
 * Stockfish Mac app by Daylen Yang, CCC, January 22, 2014 » Macintosh
 * Stockfish goes EGBB by Daniel Shawul, CCC, January 29, 2014 » Scorpio Bitbases
 * fixing the null move search "bug" by Uri Blass, CCC, February 01, 2014 » Null Move Pruning
 * Disabling Null Move Pruning in Stockfish by Louis Zulli, CCC, February 15, 2014 » Null Move Pruning
 * Threads-Test by Andreas Strangmüller, CCC, March 18, 2014 » Thread, Parallel Search
 * Stockfish haswell optimized build by Jean-Francois Romang, CCC, April 06, 2014 » BMI2
 * Huge simplification by Lyudmil Tsvetkov, CCC, April 25, 2014 » Pawn Chain
 * Stockfish zero evals by Larry Kaufman, CCC, May 02, 2014
 * Threads-Test - SF, Zappa, Komodo - 1 vs. 2, 4, 8, 16 Threads by Andreas Strangmüller, CCC, May 04, 2014 » Thread, Stockfish, Zappa, Komodo
 * investigating why stockfish is strong idea by Uri Blass, CCC, May 05, 2014
 * Threads factor: Komodo, Houdini, Stockfish and Zappa by Andreas Strangmüller, CCC, May 17, 2014 » Komodo, Houdini, Stockfish, Zappa
 * Goodbye CLOP, hello SPSA by Gary Linscott, FishCooking, May 17, 2014 » CLOP, SPSA
 * Stockfish 5 by Marco Costalba, CCC, May 31, 2014
 * Stockfish Status Report by Louis Zulli, CCC, June 27, 2014
 * GM and Rybka vs. Stockfish by Robert Maddox, CCC, August 09, 2014 » GM+Rybka vs. Stockfish
 * Nakamura vs Stockfish, public match 8/23 by Jesse L, CCC, August 17, 2014
 * Using the Transposition Table for long searches by Theodr Elwurtz, FishCooking, September 22, 2014 » Transposition Table
 * Rule of the square by Mikael, FishCooking, September 24, 2014 » Rule of the Square
 * Using the Stockfish position evaluation score to predict victory probability by unavoidablegrain, Tumblr, September 28, 2014 » Pawn Advantage, Win Percentage, and Elo
 * Threads test incl. Stockfish 5 and Komodo 8 by Andreas Strangmüller, CCC, October 09, 2014
 * Threads test - Stockfish 5 against Komodo 8 by Andreas Strangmüller, CCC, October 10, 2014 » Thread, Parallel Search, Stockfish, Komodo
 * Stockfish and accurate PV by Matthew Lai, CCC, December 25, 2014 » Principal Variation
 * Stockfish 32-bit and hardware instructions on MSVC++ by Syed Fahad, CCC, December 30, 2014 » BitScan, Population Count

2015 ...

 * Stockfish in Lozza UIs by Colin Jenkins, CCC, January 07, 2015 » Lozza, Stockfish-js
 * SF6 has been released by Joona Kiiski, CCC, January 27, 2015
 * Stockfish 6 is impressive in Behting study by Jouni Uski, CCC, January 31, 2015 » Behting Study
 * Stockfish with 16 threads - big news? by Louis Zulli, CCC, February 15, 2015 » Thread
 * Explanation for non-expert? by Louis Zulli, CCC, February 16, 2015 » Parallel Search

2016
 * Stockfish still scales poorly? by Louis Zulli, CCC, February 20, 2015
 * Measuring SF idle time by Louis Zulli, CCC, February 21, 2015
 * Better NPS scaling for Stockfish by Louis Zulli, CCC, February 27, 2015
 * Stockfish Questions by Syed Fahad, CCC, February 28, 2015
 * Best Stockfish NPS scaling yet by Louis Zulli, CCC, March 02, 2015
 * Stockfish contempt factor by Kai Laskos, CCC, March 10, 2015 » Contempt Factor
 * Improving SF passer code by Lyudmil Tsvetkov, CCC, March 26, 2015 » Connected Passed Pawns
 * Problem with SF6 and Syzygy TB by Forrest Hoch, CCC, April 01, 2015 » Syzygy Bases
 * Empirical results with Lazy SMP, YBWC, DTS by Kai Laskos, CCC, April 16, 2015 » Lazy SMP, YBWC, DTS
 * The effective speedup from 1 to 8 cpus for SF and Komodo by Adam Hair, CCC, May 31, 2015 » Parallel Search, Komodo
 * New Stockfish with Lazy_SMP, but what about the TC bug ? by Ernest Bonnem, CCC, October 26, 2015 » Parallel Search, TCEC Season 8
 * Binary for TCEC superfinal by Kiran Panditrao, FishCooking, October 30, 2015 » TCEC Season 8
 * SF binaries for TCEC superfinal by Marco Costalba, CCC, October 31, 2015
 * Stockfish dev 091115 for ANDROID by Nathanael Russell, CCC, November 09, 2015 » Android
 * Stockfish now benefits from hyperthreading by Dmitri Gusev, CCC, November 12, 2015 » Thread
 * Stockfish 7 beta 1 by Joona Kiiski, CCC, December 27, 2015
 * Another GHI example in SF (maybe) by BB+, OpenChess Forum, December 30, 2015 » Graph History Interaction
 * Stockfish 7 by Joona Kiiski, CCC, January 02, 2016
 * Threads test incl. Stockfish 7 by Andreas Strangmüller, CCC, January 11, 2016 » Thread, Parallel Search
 * Stockfish 7 progress by Carl Lumma, CCC, January 16, 2016
 * Oddity around depths 7-8 with Stockfish 6 & 7 by Ken Regan, CCC, January 21, 2016
 * Stockfish 7 and partial 6 piece syzygy problem? by Jouni Uski, CCC, March 01, 2016
 * Re: Stockfish 7 and partial 6 piece syzygy problem? by Marco Costalba, CCC, September 01, 2016

2017
 * Computer Chess Progress: Stockfish 7 vs Ruffian 1.0.5 by Martin Fierz, CCC, March 17, 2016 » Ruffian
 * Natural TB by Marco Costalba, CCC, May 29, 2016 » Syzygy Bases
 * Stockfish eval output by Erin Dame, CCC, August 27, 2016 » Wrong Color Bishop and Rook Pawn
 * Re: Beginner's guide to graphical profiling by Marco Costalba, CCC, September 10, 2016 » Profiling
 * ELO inflation ha ha ha by Henk van den Belt, CCC, September 16, 2016 » Delphil, Match Statistics, Playing Strength, TCEC Season 9
 * pin-aware see by Ronald de Man, FishCooking, September 14, 2016 » SEE - The Swap Algorithm, Pin
 * Illegal moves in SEE by Stephane Nicolet, FishCooking, September 22, 2016 » SEE - The Swap Algorithm
 * Stockfish underpromotes much more often than Komodo by Kai Laskos, CCC, October 05, 2016 » Komodo, Match Statistics, Promotions
 * couple of questions about stockfish code ? by Mahmoud Uthman, CCC, October 26, 2016 » SIMD and SWAR Techniques, Tapered Eval
 * Stockfish 8 by Marco Costalba, FishCooking, November 01, 2016
 * Stockfish 8 official by Marco Costalba, CCC, November 01, 2016
 * NUMA test compilation by Joachim Müller, FishCooking, November 05, 2016 » NUMA
 * Stockfish 8 - Double time control vs. 2 threads by Andreas Strangmüller, CCC, November 15, 2016 » Doubling TC, Diminishing Returns, Playing Strength, Lazy SMP
 * Stockfish benchmark data by Adam Hair, OpenChess Forum, November 27, 2016
 * The new chess rules (5-fold repetition and 75-move draw) by Lyudmil Antonov, FishCooking, November 29, 2016 » Repetitions, Fifty-move Rule
 * Scoutfish: powerful chess query tool by Marco Costalba, CCC, December 11, 2016 » Databases, Portable Game Notation, Scoutfish
 * SF Progression since Fishtest inception by Adam Hair, CCC, January 14, 2017 » Fishtest
 * Re: Chessprogams with the most chessknowing by Marco Costalba, CCC, February 19, 2017 » Search versus Evaluation
 * Stockfish bench in i486 & Pentium 75mhz ! by hammerklavier, CCC, April 29, 2017
 * Re: Stockfish bench ...

2018 2019
 * Symmetric multiprocessing (SMP) scaling - SF8 and K10.4 by Andreas Strangmüller, CCC, May 05, 2017 » Lazy SMP, Komodo
 * Symmetric multiprocessing (SMP) scaling - SF8 Contempt=10 by Andreas Strangmüller, CCC, May 13, 2017 » SMP, Contempt Factor
 * Stockfish version with hash saving capability by Daniel José Queraltó, CCC, July 25, 2017 » Persistent Hash Table
 * Natural TB (take 2) by Marco Costalba, CCC, August 22, 2017 » Syzygy Bases
 * Approximating Stockfish's Evaluation by PSQTs by Thomas Dybdahl Ahle, CCC, August 23, 2017 » Regression, Piece-Square Tables
 * Stockfish no progress in 2month and half, why ? by Jean Baptiste, CCC, August 28, 2017
 * Stockfish testing at STC and LTC: one question by Jouni Uski, CCC, September 19, 2017
 * Scaling from FGRL results with top 3 engines by Kai Laskos, CCC, September 26, 2017 » FGRL, Houdini, Komodo
 * AlphaZero vs Stockfish by Bigler, CCC, December 06, 2017 » AlphaZero vs. Stockfish
 * A branch to test the Monte Carlo algorithm in Stockfish by Stephane Nicolet, FishCooking, December 06, 2017 » Monte-Carlo Tree Search, AlphaZero
 * Reactions about AlphaZero from top GMs... by Norman Schmidt, CCC, December 08, 2017 » AlphaZero: Reactions From Top GMs, Stockfish Author, Tord Romstad
 * MCTS wrapper for StockFish by Jonathan Baxter, FishCooking, December 19, 2017 » Monte-Carlo Tree Search
 * Stockfish 8 - Initial position until depth 59 by Andreas Strangmüller, CCC, January 16, 2018 » Initial Position
 * New Stockfish contempt by Jouni Uski, CCC, January 29, 2018 » Contempt Factor
 * Contributors in the last two years by Stephane Nicolet, FishCooking, Jnauary 30, 2018
 * Stockfish 9 by Marco Costalba, CCC, February 01, 2018
 * Elo measurement of contempt in SF in self-play by Michel Van den Bergh, CCC, March 10, 2018 » Contempt, Playing Strength
 * Stockfish 180113 - Initial position until depth 65 by Andreas Strangmüller, CCC, March 27, 2018 » Initial Position
 * Stockfish and serious hardware: 384 threads by Jouni Uski, CCC, July 08, 2018 » Thread
 * Stockfish 10 - Call for Binaries by Daylen Yang, FishCooking, November 29, 2018
 * Re: piece lists advantage with bit-boards? by Ronald de Man, CCC, December 26, 2018 » Piece-Lists, asmFish
 * Re: What's the best Lazy SMP logic? by Sven Schüle, CCC, January 06, 2019 » Lazy SMP in Stockfish
 * Training the trainer: how is it done for Stockfish? by Marc-Philippe Huget, CCC, March 01, 2019 » Monte-Carlo Tree Search
 * Some NUMA data for Stockfish-dev and Cfish-dev by Louis Zulli, CCC, June 17, 2019 » NUMA, CFish
 * Why does stockfish randomise draw evaluations? by Vincent Tang, CCC, September 01, 2019 » Draw, Draw Evaluation, Draw Score, Search with Random Leaf Values
 * Help needed testing vectorized Stockfish pawns.cpp... by Nick Pelling, FishCooking, September 23, 2019
 * mg vs eg eval by Joost VandeVondele, FishCooking, October 06, 2019 » Middlegame, Endgame, Tapered Eval
 * Stockfish contempt testing by Leonardo Ljubičić, FishCooking, October 29, 2019 » Contempt
 * some questions about singular search in Stockfish by Jon Dart, CCC, November 01, 2019 » Singular Extensions
 * "stat score bonus" in stockfish by Vivien Clauzon, CCC, November 01, 2019
 * Stockfish 10 was released 29.11.2018 by Jouni Uski, CCC, December 01, 2019

2020 ...

 * lazy smp behaviour of stockfish by Daniel Shawul, FishCooking, January 05, 2020 » Lazy SMP
 * The Stockfish of shogi by Larry Kaufman, CCC, January 07, 2020 » NNUE, Shogi
 * Stockfish 11 by Stephane Nicolet, CCC, January 18, 2020
 * Stockfish Reverts 5 Recent Patches by Deberger, CCC, February 01, 2020
 * Re: Stockfish Reverts 5 Recent Patches by Michel Van den Bergh, CCC, February 02, 2020 » SPRT

2021
 * Stockfish and latest +6 ELO patch! by Jouni Uski, CCC, March 05, 2020 » Distance, Space-Time Tradeoff
 * Null move by Robert Pope, CCC, April 24, 2020 » Null Move Pruning
 * Stockfish_dev is probably stronger than Sargon 1978 v1.00 by Kai Laskos, CCC, May 29, 2020 » Sargon
 * Stockfish NN release (NNUE) by Henk Drost, CCC, May 31, 2020 » NNUE, Stockfish NNUE
 * Stockfish has included WDL stats in engine output by Deberger, CCC, July 02, 2020 » Pawn Advantage, Win Percentage, and Elo
 * stockfishNNUE vs others (TCEC 18 bonus) by Warren D. Smith, FishCooking, July 14, 2020
 * Can the sardine! NNUE clobbers SF by Henk Drost, CCC, July 16, 2020 » Stockfish NNUE
 * The most stupid idea by the Stockfish Team by Damir, CCC, August 30, 2020 » Stockfish NNUE
 * Stockfish 12 by Joost VandeVondele, FishCooking, September 02, 2020
 * Stockfish 12 is released today! by Nay Lin Tun, CCC, September 02, 2020
 * Stockfish 12 has arrived! by daniel71, CCC, September 02, 2020
 * SF NNUE/Classical by Fauzi, FishCooking, October 05, 2020 » Stockfish NNUE
 * Re: Stockfish bench in i486 & Pentium 75mhz ! by Vincent Lejeune, CCC, October 11, 2020 » Stockfish bench ...
 * Re: Raspberry Pi 4 compiled chess engines by Rasmus Althoff, CCC, November 16, 2020 » Raspberry Pi
 * Shouldn't positional attributes drive SF's NNUE input features (rather than king position)? by Nick Pelling, FishCooking, January 10, 2021 » Stockfish NNUE
 * Stockfish 13 by Joost VandeVondele, FishCooking, February 19, 2021
 * Stockfish 13 merged on github by Joshua Shriver, CCC, February 19, 2021
 * Setting up Stockfish on a server by Jon12345, CCC, March 29, 2021 » Chess Server
 * Joking FTW, Seriously by borg, LCZero blog, April 25, 2021
 * Stockfish with new NNUE architecture and bigger net released by Stefan Pohl, CCC, May 19, 2021
 * The importance of open data by borg, LCZero blog, June 15, 2021
 * will Tcec allow Stockfish with a Leela net to play? by Wilson, CCC, June 17, 2021 » TCEC Season 21
 * Re: will Tcec allow Stockfish with a Leela net to play? by Connor McMonigle, CCC, June 17, 2021


 * Stockfish 14 release round the corner by Prasanna Bandihole, CCC, July 02, 2021
 * Before things become more messy than they already are by Ed Schröder, CCC, July 02, 2021
 * Stockfish 14 has been released by Madeleine Birchfield, CCC, July 02, 2021

=Blog Posts=
 * Stockfish Blog

2014

 * One chess champion per laptop by Roberto Perez-Franco, MIT's The Tech, January 15, 2014 » TCEC Season 5

2015 ...

 * And then there were two by John Hartmann, ChessBase News, June 09, 2015 » Komodo, Stockfish
 * Depth of Satisficing by Ken Regan, Gödel's Lost Letter and P=NP, October 06, 2015 » Depth, Match Statistics, Pawn Advantage, Win Percentage, and Elo, Stockfish, Komodo
 * A Chess Firewall at Zero? by Ken Regan, Gödel's Lost Letter and P=NP, January 21, 2016
 * Stockfish 8, November 01, 2016
 * Stockfish 9, February 09, 2018
 * Stockfish 10, December 01, 2018

2020 ...

 * Stockfish 11, The Stockfish Team, January 15, 2020
 * Introducing NNUE Evaluation, August 07, 2020
 * Stockfish 12, The Stockfish Team, September 02, 2020
 * Stockfish 13, The Stockfish Team, February 19, 2021
 * Stockfish 14, The Stockfish Team, July 02, 2021

=External Links=

Chess Engine

 * Stockfish - Open Source Chess Engine
 * official-stockfish/Stockfish · GitHub
 * GitHub - nodchip/Stockfish: UCI chess engine (Stockfish NNUE by Nodchip)
 * zamar · GitHub by Joona Kiiski
 * NCM Stockfish Dev Builds
 * Stockfish Development Versions hosted by Roman Korba
 * Stockfish (chess) from Wikipedia

Issues

 * Issues · official-stockfish/Stockfish · GitHub
 * NNUE merge · Issue #2823 · official-stockfish/Stockfish · GitHub by Joost VandeVondele, July 25, 2020
 * NNUE ideas and discussion (post-merge) Issue #2915 official-stockfish/Stockfish · GitHub by Joost VandeVondele, August 06, 2020
 * NNUE eval rotate vs mirror · Issue #3021 · official-stockfish/Stockfish · GitHub by Terje Kirstihagen, August 18, 2020

Pull Requests

 * Pull requests · official-stockfish/Stockfish · GitHub
 * Update default net to nn-8a08400ed089.nnue by Sopel97 · Pull Request #3474 · official-stockfish/Stockfish · GitHub by Tomasz Sobczyk

Testing

 * Get Involved - Stockfish - Powerful Open Source Chess Engine
 * Stockfish Testing Framework » Fishtest
 * Stockfish Evaluation Guide » Stockfish Evaluation Guide
 * GitHub - glinscott/fishtest: Stockfish testing
 * Creating my first test · glinscott/fishtest Wiki · GitHub
 * Fishtest mathematics · glinscott/fishtest Wiki · GitHub


 * SPSA Tuner for Stockfish Chess Engine » SPSA
 * FishCooking - Google Groups a discussion group for developers and testers of Stockfish chess engine
 * Adam's Computer Chess Pages: Stockfish Progression by Adam Hair » Fishtest

Rating Lists

 * Stockfish from CCRL 40/15
 * Stockfish in CCRL Blitz

Matches

 * Can a GM and Rybka beat Stockfish? by GM Daniel Naroditsky, Chess.com, August 08, 2014 » GM+Rybka vs. Stockfish
 * Stockfish Outlasts "Rybkamura" by FM Mike Klein, Chess.com, August 24, 2014
 * AlphaZero: Reactions From Top GMs, Stockfish Author by Peter Doggers, Chess.com, December 08, 2017 » AlphaZero vs. Stockfish

Interviews

 * Computerschach, Interview with Tord Romstad (Norway), Joona Kiiski (Finland) and Marco Costalba (Italy) by Frank Quisinsky, March 29, 2010
 * Stockfish 4 to play in the new season of TCEC | Chessdom - Short interview with the Stockfish team, August 22, 2013 » TCEC, TCEC Season 5

Videos

 * How do modern chess engines work? | Video, Talk by Daylen Yang, TNG | Big Techday 8, June 12, 2015
 * Parallelism and Selectivity in Game Tree Search | Video, Talk by Tord Romstad, TNG | Big Techday 8, June 12, 2015
 * How Modern Chess Programs Work | Video by Tord Romstad, flatMap(Oslo), May 02, 2017

Misc

 * Stockfish from Wikipedia
 * Lofoten Stockfish Museum from Wikipedia
 * Postcards from the Lofoten Islands from Giving Up The Ghost, May 29, 2012 » Stockfish and Gulls

=References=

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