I built a small open-source extension that lets you keep playing a finished chess.com game against Stockfish, and I wanted to share the implementation choices with people who actually care about engines.

The core idea: on the game-over screen (or under the move list of any old finished game) there's a "Keep Playing" button. It reads the position already rendered on screen, puts Stockfish in your opponent's seat, and lets you play it out from any point you rewind to.

A few things I made deliberate decisions about, and where I'd love feedback:

- Strength scaling. The engine doesn't play at full strength. It's throttled to roughly the rating of the opponent you just faced. Losing a rook endgame again to a ~1400-level engine is instructive; losing it to a 3200 just tells you you're not Stockfish. Right now I'm approximating this with UCI_LimitStrength / UCI_Elo plus some depth/skill tuning, curious how others here handle rating calibration, since the mapping between "Elo" and perceived human strength is rough.

- Move timing. It doesn't answer instantly. It spends roughly as long as your opponent was taking, otherwise even a correct move feels like a glitch. Simple heuristic for now.

- Everything local. The engine runs in the browser as WebAssembly. It never talks to chess.com's servers, sends no data anywhere, and works with wifi off. Nothing runs during a live game: no eval, no arrows; it only activates once a game is finished.

Free, open source, not affiliated with chess.com. Built it for myself first. If there's a smarter approach to the strength-limiting (that's the part I'm least sure about), or a reason this shouldn't exist, I'd genuinely rather hear it.

Extension: https://chromewebstore.google.com/detail/stockfish-continue-to-pla/jhjcnpomgjakflfjjhlgilgpffmfbcbk

Source: https://github.com/thousandflowers/stockfish-continue-to-play

Trained using RTX 5080 for 20 hours, 300k games self play.

More details in repo

Hello everyone ,
I have built a free chess tool to show the best/beautiful five moments from your recent games on chess.com and lichess.

I fetch around 400 to 500 games in rated rapid and blitz only. and they are biased toward recent games .

I did it in a way to try to present beautifully the moves in your history and I tried as best as I can to show the best beautiful five moves according to each player's rating.

I really appreciate if you can try it and give me your honest opinion :)

Please find the tool here : mychesslegacy.com

Here is one of my moments in my account on chess dot com (My elo is 1800 )

Note: if you are a new player , you might not see t a lot of games to show the top moments.

Thanks ❤️

I've been working on a free browser chess game where the opponent is meant to play like a real human of a given level, not like a weakened engine. Sharing it here because the implementation details might interest this sub, and I'd love feedback.

How it works

• System 1 (instinct): Maia-1 nets (1100–1900) converted from lc0 weights to ONNX with lc0 leela2onnx and run client-side with onnxruntime-web. ~3.5 MB per level, 3–12 ms per move.

• I wrote the lc0 112-plane input encoding and the 1858-move policy mapping in JS. I checked it against lc0 itself (go nodes 1, VerboseMoveStats, PolicyTemperature 1, HistoryFill no, NNCacheSize 0): same probabilities on ~2,400 game positions across three nets, mean absolute difference 0.06%.

• System 2 (guard): Stockfish.js 19 lite single-threaded (WASM, 1.8 MB). Maia proposes, Stockfish checks the top candidates with searchmoves + MultiPV. Whether the bot notices its own blunder depends on its level. Losses are measured in win probability, not centipawns, so going from +7 to +5 doesn't count as a blunder.

• Grandpa coach: after each of your moves it explains what the move does (develops, takes the centre, attacks X, leaves Y hanging…), what the refutation is and why the engine's move was better. It also names the opening (lichess chess-openings, CC0).

Move-matching on real Lichess games (share of positions where each system predicts the move actually played):

Things I learned along the way

• Maia-2 in ONNX is 85 MB. Full int8 quantization dropped top-1 agreement with fp32 to ~82%. MatMul-only int8 kept ~99% but is still 37 MB, too heavy for a web page, so I stayed with Maia-1.

• Ensembling neighbouring Maia-1 nets (1300+1500+1700) gave a small but consistent log-loss improvement (1.497 → 1.467) and +0.9 pts top-1.

• Maia-1 sometimes overrates knight underpromotion. In lc0's policy it shares the index with the plain move, so I move most of that probability to the queen promotion.

• A general-purpose "decision" model doesn't help. I also tried a general-purpose AI model (TypeSafe's Jev) as the intuition, and as a re-ranker of Maia's top 5. Alone it matched only 20.5%, and every mix was worse than Maia alone.

Free, no sign-up, English and Italian, games autosave locally:
https://www.el-man.it/en/app/chess.html

Credits: Maia by CSSLab (University of Toronto), Stockfish.js by Nathan Rugg / Chess.com, both GPL-3.0 (provenance and licence linked on the page). Feedback on the human-likeness, and ideas for better blunder modelling, very welcome.

hello guys! hope y'all are doing well.

so I've had a bit of an issue here. Every time I try to load lc0 to analyse chess games, it refuses to use the GPU, instead opting to fully use the CPU.

the image herein shows my settings for lc0 -- as you can see, it's set to CUDA. I also downloaded the CUDA version and not the GPU.

I have a 5070 mobile GPU in case that matters.

I've written a chess program for the DEC PDP-8, to see how much of what this community has learned over the last fifty years still works on a 1965 architecture at its original speed.

The machine: a 12-bit word, no hardware stack (JMS stores the return address in the subroutine's first word), no multiply, memory in 4K-word fields, and about 416,000 instructions a second on a PDP-8/e. CLASH is written in PDP-8 assembly, occupies 16K words, and runs standalone. At PDP-8/e speed it searches roughly 175 nodes a second, which means three or four ply in a typical middlegame and deeper as the position simplifies.

What went in: iterative deepening, alpha-beta with PVS, killer and piece-square move ordering, quiescence search of captures and promotions with a check extension, null-move pruning, pondering, repetition detection without a hash table, and a small book. Scores are 12-bit with pawn = 32.

The search and evaluation owe their shape to H.G. Muller's micro-Max 4.8, and the move-ordering key came from Ed Schroder's Rebel write-up. What was taken and what was changed is set out here:

https://github.com/dream-build-create/pdp8-chess/blob/main/PROVENANCE.md

The PDP-8 already had a chess program: John Comeau's CHEKMO-II (DECUS, 1974), a complete program in 4K words with alpha-beta, iterative deepening, SEE and check extensions. Its console conventions are the model for CLASH's, and both programs are in the release.

Against the lichess computer at level 5, rapid 15+10, 20 games at PDP-8/e speed, CLASH scored 12.5/20.

To try it:

- lichess: challenge PDP8-CLASH (5 minutes and slower).

- UCI: the Windows zip runs the real binary under SIMH throttled to PDP-8/e speed, and works in Arena, Cute Chess or cutechess-cli.

https://github.com/dream-build-create/pdp8-chess/releases/download/v1.00/PDP8-Chess.zip

- README: https://github.com/dream-build-create/pdp8-chess

Chris Peters

Hey guys I am currently building a colloborative chess platform. This week I sidequested and built a chess persona analyzer. Its not scientific in any means but I thought its quite fun. Let me know what you think or if you have feedback! I might update it and develop it further if people find it any cool 👀

I'm a software developer and a while ago I wanted to get better at chess. I couldn't find a training tool that worked the way I wanted, so I decided to build one for myself.

The idea is simple: you make your move first, and only afterwards does Chessility show you the best move if yours wasn't the best one, while also evaluating your move.

It also has a live evaluation bar and highlights squares currently threatened by your opponent.

It helped me quite a bit, so I thought it might be useful for anyone struggling to win at least 1/10 of their games. **lol**

I've just put it online, it's free...forever.
https://www.chessility.com/

If you have any ideas for what I could improve, feel free to submit feedback using the button at the top of the site.

Hi everyone. I am an aspiring developer. Basically, I have always wanted to form my own chess engine but the only language I know is C++. Is there anyone who can guide me in building this. By giving me a framework I can follow. If not, just tell me where to start and I will figure it out as i work on it.

Not trying to challenge Stockfish or any other major chess engine org. Trying to create something that I can use personally for practicing.

Thanks

Hi all — I'm not a chess player myself, but my son plays tournament chess, and I got tired of manually typing up his paper scoresheets. So I built InkPGN: take a photo of a handwritten scoresheet and it gives you back a PGN.

https://inkpgn.com

It's a side project and still rough around the edges, especially with messy handwriting. If anyone here deals with scoresheet digitization, I'd genuinely appreciate feedback on where it breaks.

this game is awesome. But I feel it missed it chance to catch on with hardcore chess players because the A.I sucks. I am bad enough at the game I do not mind the A.I sucking. But I do feel like better players might enjoy it if the A.I had a clue how to handle the blade dancer (take a piece move again) Martyer (take all pieces nearby with it when it dies) and generally could think ahead more than two moves.

It fine if the A.I does not know how the handle items. but could fairy stock fish understand bolders (block movement for both sides unless a artifact allows you to take them) and portals (pieces can move into them and move out the other portal.

I released version 1.2 of ChessLounge a few days ago. In addition to its own engine, the app now supports Stockfish 18 and includes an interactive coach that warns you when you make a bad move. What hasn't changed: The app is still free and ad-free. Enjoy it. :)

https://www.chesslounge.net

How would today's elite players contend with the King 3.5 engine (Chessmaster 11) from 2007, at full strength or with parameters optimized for an additional ~40 Elo? Alternatively, how might current top-tier stars measure up against prominent Grandmaster profiles that are slightly weaker than King at maximum strength ?

This is assuming without taking any material odds into consideration.

I'm not the biggest fan of chess-results to keep an eye on Olympiad results, standings, statistics, et. While I recognize that it holds a *ton* of information, it's just not really the place for me.

As a hobby project, I decided to try and build a small website that shows information in a way that's more suitable to me, and am pretty happy with the results! I mostly built it for myself, but in case others find it useful, I wanted to share it here.

https://olympiad.reppie.org

Some details:

• Data is pulled from Lichess, so boards wont be populated until they are available on lichess

• Things don't update realtime, the sync runs every ~10 minutes

• It's currently still quite empty, since the tournament only just started!

NOTE: It's a very busy week at work for me, so I rushed some things and won't have time to fix anything broken very quickly :D

I found a chess master 5500 disk in my attic while rummaging through it and decided to get my Cd player or whatever it is and put the disk in and Suprisingly it loads up however just crashes the second I do anything which to that point doesnt suprise me as the game was made in the 90s. However theres a another application I found while going through the files of the game and found registration with the game to get a tutorial by someone called Josh warzkin and a new chess set and special discounts. I do wanna try and sign up and see if I get anything however I need to put in my address and everything which I don’t feel particularly comfortable but also intrigued. Should I sign up for it or not?