Stockfish Blog

Updates from the Stockfish team.

Stockfish 16.1

Today, we have the pleasure to announce Stockfish 16.1. As always, you can freely download it at and use it in the GUI of your choice.

Don’t forget to join our Discord server to get in touch with the community of developers and users of the…

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Stockfish 16

A new major release of Stockfish is now available at

Quality of chess play

Stockfish continues to demonstrate its ability to discover superior moves with remarkable speed. In self-play against Stockfish 15, this new release gains up to 50 Elo and wins…

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Stockfish 15.1

Today, we have the pleasure to announce Stockfish 15.1.

As usual, downloads will be freely available at

Elo gain and competition results

With this release, version 5 of the NNUE neural net architecture has been introduced, and the training data has…

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ChessBase GmbH and the Stockfish team reach an agreement and end their legal dispute

More than one year ago, leading developers of the chess engine Stockfish, Tord Romstad and Stéphane Nicolet, with broad support from the development community, filed suit against ChessBase GmbH before the District Court Munich I (Az. 42 0 9765/21) to enforce the GNU General…

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Public court hearing soon!

As announced nearly one year ago, leading Stockfish developers have filed suit against ChessBase to enforce their license termination after repeated copyright violation by ChessBase. The court hearing in the case Tord Romstad and Stéphane Nicolet vs. ChessBase GmbH will take…

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Stockfish 15

A new major release of Stockfish is now available at

Stockfish 15 continues to push the boundaries of chess, providing unrivalled analysis and playing strength. In our testing, Stockfish 15 is ahead of Stockfish 14 by 36 Elo points and wins nine times…

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Stockfish 14.1

Today, we have the pleasure to announce Stockfish 14.1.

As usual, downloads will be freely available at

With Stockfish 14.1 our users get access to the strongest chess engine available today. In the period leading up to this release, Stockfish…

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Our lawsuit against ChessBase

The Stockfish project strongly believes in free and open-source software and data. Collaboration is what made this engine the strongest chess engine in the world. We license our software using the GNU General Public License, Version 3 (GPL) with the intent to guarantee all chess…

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Stockfish 14

Today, we have the pleasure to announce Stockfish 14.

As usual, downloads will be freely available at

The engine is now significantly stronger than just a few months ago, and wins four times more game pairs than it loses against the previous release…

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Stockfish 13

It is our pleasure to release Stockfish 13 to chess fans worldwide. As usual, downloads are freely available at

The Stockfish project builds on a thriving community of enthusiasts who contribute their expertise, time, and resources to build a free and…

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Statement on Fat Fritz 2

Stockfish is an open-source project, sharing and freely distributing the code, tools and data needed to deliver this chess engine. We do this because we are convinced that open software and open data are key ingredients to make rapid progress, and thus for the benefit of our…

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Stockfish 12

It is our pleasure to release Stockfish 12 to users worldwide.

Downloads are freely available at

This version 12 of Stockfish plays significantly stronger than any of its predecessors. In a match against Stockfish 11, Stockfish 12 will…

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Introducing NNUE Evaluation

As of August 6, the efficiently updatable neural network (NNUE) evaluation has landed in the Stockfish repo!

What is NNUE?

Both the NNUE and the classical evaluations are available, and can be used to assign a value to a position that is later used in alpha-beta (PVS) search to…

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Stockfish 11

It is our pleasure to release Stockfish 11 to our fans and supporters.

Downloads are freely available at

This version 11 of Stockfish is 50 Elo stronger than the last version, and 150 Elo stronger than the version which famously lost a match to…

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Stockfish 10

Official release version of Stockfish 10.

Downloads are available at

This is also the 10th anniversary version of the Stockfish project, which started exactly ten years ago! I wish to extend a huge thank you to all contributors and authors in…

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Stockfish 9

I am pleased to announce that Stockfish 9 is out.

You can download the offical builds from here

I would like to thank all the amazing people that made this release possible. All our testers and our developers, all the people that donate CPU…

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Stockfish 8

Stockfish 8 is out!

This is the result of the effort of many people along many months: it has been a huge and hard effort and I would like to thank all the testers for their relentless patience, determination and creativity. I would like to thank all the people supporting us with…

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Stockfish 7

Stockfish 7 is out!

  • This release is around 60 ELO stronger than Stockfish 6 in self play.
  • SMP algorithm has been changed from YBW to Lazy SMP.
  • Gary Linscott is now officially listed as a co-author.

Download it from

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Stockfish 6

Stockfish 6 is now available!

This release adds support for Syzygy endgame tablebases, and is 50 ELO stronger than Stockfish 5 in self play.

We recommend that you download Syzygy bases via torrent from here:

Stockfish 6 binaries are…

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Stockfish 5

Stockfish 5 is now available!

This is the version that won TCEC Season 6 but without table-bases.

From SF DD released at end of November of last year a lot of work has been done:

44 files changed, 2272 insertions(+), 2764 deletions(-)

By many contributors both in patches:

  • Arjun…
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Stockfish DD

This is a new release of Stockfish after the last TCEC season. It is almost the same version that played the superfinal against Komodo.

Download Browse the source code

For people compiling themselves, please verify signature is correct running ‘stockfish bench’ from a…

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Stockfish 4

Stockfish 4 has been released. You can download at or browse the sources at

Diffs from last version is: 43 files changed, 1534 insertions(+), 1703 deletions(-)

So 169 lines of code less but should be quite stronger…

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Stockfish 3

This is Stockfish 3.

The big news of this version, and the reason why we have bumped version number to 3 is not due to ELO increase (that anyhow should be interesting) nor to some cool feature, but it is due to the new super awesome testing framework that Gary setup and currently…

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Stockfish 2.3.1

This version fixes a Chess960 bug. It also has an ELO increase:

Stockfish bench signature is 5423738.

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Stockfish 2.3

44 files changed, 3486 insertions(+), 3778 deletions(-)

ELO increase is very limited, it is mainly a minor release to flush the accumulated work. From the user point of view the biggest thing is that SF should not crash anymore even with many threads because a nasty SMP bug…

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Stockfish 2.2.2

The 64-bit Windows compiles are built with GCC instead of Intel, so there is a 5-6% speed increase. Very few code changes: it should be a bit faster and a bug is fixed where Stockfish in some (rare) positions erroneously moves immediately without thinking.

Stockfish’s new…

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Stockfish 2.2.1

This version fixes the time management issue. The signature is 5457475.


Update Jan 6, 2012: Stockfish 2.2.1 has been reposted to fix a compatibility issue with SSE4.2 Phenom processors.

Update Jan 7, 2012: Stockfish 2.2.1 for Android has been reposted to fix an issue in…

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Stockfish 2.2

To start the new year with a fresh new base I’d like to release Stockfish 2.2. This should be really a small improvement ELO wise, I have tested it against SF 2.1.1 JA and in single core I got +10 ELO, we think in multi core we should gain some more, but remain anyhow…

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Stockfish 2.1.1

This is a maintenance release to fix the book reading issue reported by some users. As an added benefit, Jim’s build should be now a little faster on Intel CPU (4% on 64-bit and almost 6% on 32-bit).

This is a non functional change release so there is no need to retest…

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Stockfish 2.1

This is Stockfish 2.1.

Diff stats from 2.0.1 says: 54 files changed, 4138 insertions(+), 5656 deletions(-)

So more than 1500 lines of code removed for this release.

In this release a new skill level facility has been introduced. Stockfish can be set to skill level 20 (default) to…

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Stockfish 2.0.1

This is a maintenance release. No functional change and no ELO increase from 2.0.

Main fixes are:

  • Fix a crash in multi-pv analysis
  • Fix Chess960 support
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Stockfish 2.0

Diff stats from 1.9.1 says:

54 files changed, 2130 insertions(+), 2812 deletions(-)

So almost 700 lines of code removed for this release.

Actually we didn’t plan to release now, but it happens that our test framework will be down for a couple of weeks due to new year…

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