Reckless(white) beats Stockfish(black) in an embarrassing fashion in the current ccc rapid event in chess.com. Meanwhile Stockfish was only able to draw with the white pieces with the same opening.

Here's the link: https://www.chess.com/computer-chess-championship#event=441&game=206

Inspired by YouTube challenges where GMs must mate amateurs within 20–25 moves, I wondered: how fast could a chess engine checkmate a human if that were its only objective?

What I built: an engine explicitly optimized for speed of mate against humans. Details:

• Openings: mined ~100GB of Lichess games to build Elo-specific opening books, selecting openings with the shortest average games rather than best evaluations.

• Midgame: uses Maia2 to predict likely human moves instead of assuming optimal play. It plays moves that an engine like stockfish would destroy, but that a human will probably miss.

• Endgame: switches to strict mate-solving logic (not forced mates, but most likely mates against a human).

Why standard engines struggle: even aggressive engines optimize for objective soundness and win probability instead of risky lines that might mate much faster. For example, Leela with high Cpuct and Komodo with high contempt can checkmate me in -41 moves whereas I only last ~34 moves vs this one.

Try it here: http://siegechess.com

I’d love links to any work/projects on minimizing time-to-mate against human play (I couldn't find any). I have no intent to ever make money from this. Just a fun project.

Edit: January 4th 1:52 pm EST: I'm going to stop/start the engine to fix a bug. This will probably cause the 6 games that are currently being played to end (engine will time out). sorry.

Edit2: January 7th 554 PM EST: Going to fix a few things, games/page will lag or crash for a bit. sorry.

Would human direction or collaboration provide any additional value or is Stockfish so far ahead that human collaboration would just be a drag?

I've been working on an engine called STILLWATER for a while now and finally feel like it's worth showing off. The unusual part is that it doesn't search the way engines normally do. There's no alpha-beta, no MCTS, no tree of any kind. Instead it keeps what I can best describe as a pond: a lattice of beliefs about positions it has seen, and when new evaluations flow in, the whole thing settles toward a new equilibrium, like ripples dying out. A position it examined three moves ago is still sitting there in the pond, so nothing gets recomputed and knowledge carries over across moves and even between games. It also proves things outright (forced mates, dead draws) and those proofs are kept forever, so it slowly grows its own private tablebase from experience. The weirdest property in practice is that it barely cares about time. It reaches its conclusion in a couple of seconds and more thinking changes very little, which makes it play blitz at nearly the same level it plays rapid. It recently held the latest Stockfish dev build to a draw in a 5+3 game while using about two seconds a move, and our measurements against fixed anchors put it in the 3400 CCRL neighborhood.

It plays on Lichess at https://lichess.org/@/stillwater_bot_2. Fair warning, the account is brand new so the rating you'll see is provisional nonsense, the old account had a long history of games from much weaker early versions so i retired it. It accepts basically any standard challenge from 3+0 up through classical, humans and bots alike. If you play it, the experience is a bit strange: it moves almost instantly when it considers the position settled and then suddenly burns half a minute on moves it finds unclear. Come throw some games at it, especially blitz, and if you run a bot yourself I'd love to see it in the challenge queue. Happy to answer questions about the design in the comments as long as they're not "post the source" (not yet sry).

https://www.chessigma.com/

Hello ComputerChess friends - for the last 2 years I wanted to see how fast a movegenerator in chess can get. At the end my approach was 6-8x faster than the current fastest C implementation - and is as of 2021 the fastest movegen in chess!

Article: https://www.codeproject.com/Articles/5313417/Worlds-fastest-Bitboard-Chess-Movegenerator
Sourcecode: https://github.com/Gigantua/Gigantua

Chess is such a beautiful programming problem to solve - since one board contains exactly 64 squares. So we can define a Bitbord of all pawns to be just one single uint64_t. Same for all other 11 piecetypes.

Doing it this way enables all 8 pawns to walk forward like this: (WPawn << 8) & Empty. Which normally would need 8 if statements to generate - but can be done in 2 branchless instruction with a bitbord. Things like where a piece can move become extremely pleasant to write:

uint64_t move = Seemap & EnemyOrEmpty & noCheck

I also was able to implement a visitor pattern in the first ever chess related piece of code. Instead of having a movelist - we pass a small template inlined function which is the callback for every possible move. Instead of generating a list - this movegenerator decides the instant it sees a possible move what to do with it! Castling and Enpassant gets compiled away by if constexpr when its not on the board - or possible anymore!

- First ever Make-Unmake free Chess Movegenertaor

- Fastest bmi2 Pext intrinsics slider lookup _pextu64()

- Original legal move generator - almost completely branchless. Solves all checks and pins with only and / not instructions - and a few lookups for king / knight - sliders! No "If" needed for 99% of chess

- First ever complete Template gamestate. The code does not need to evaluate a Enpassant move if the enemy didnt push - or any castling move if its not possible to castle anymore. C++ if constexpr really helps a lot!

Performance: Perft(6) Time taken: 85ms

Moves: 119060324 Checks: 809099 Checkmates: 10828

That is 119 Million in 85ms or just about 1400 Million nodes per second. For the staring position. This is the slowest position and most positions get around 2 Billion nodes per second and 1 thread.

This approach is 6-8x faster than the currently leading movegenerator written in C.

Anyways I dont want the post be too long. C++ is an awesome language for performance! - Please read the Article and Source if you are interested!

Article: https://www.codeproject.com/Articles/5313417/Worlds-fastest-Bitboard-Chess-Movegenerator

Sourcecode: https://github.com/Gigantua/Gigantua

If you like this - consider buying me a coffee :) - https://www.buymeacoffee.com/Pontifex

Hi everyone,

Link: https://www.jimmyrustles.com/ccrlchallenger

I've been working on this project for the past few weeks. It's a website that allows you to play against engines from the CCRL in your browser. I thought it'd be fun to be able to play against CCRL engines without having to download and run them, so I made this site.

There are 118 different open source engines, all taken from the CCRL. I tried to include as many engines as I possibly could, but I could only include engines with Windows releases and permissive licenses that passed testing, which left me with 118 engines.

You can give the engine 1ms to 5 seconds of move time and play the games completely in the browser.

Please try it out and let me know what you think.

I spent about six months making an operating system whose only job is playing chess. It boots straight into Chess. It is not a full OS with a file system or scheduling but it can boot from bare metal.

It runs in QEMU, other virtual machines and hardware with legacy BIOS from a USB or CD drive. I spent about 6 months across the boot loader and chess engine. It is entirely open-source for you to tinker with. There is also a Windows Installer for less technical users.

All feedback is welcome!

Thank you for Paledoptera for the artwork. Find more of their work here: https://linktr.ee/paledoptera

Website: https://chessos.xyz (includes Github link)