LINEACHESS 2.0 — UCI Engine + GUI (Windows)

[Chessgate]

Hello everyone,

We are releasing **LINEACHESS 2.0**, a free chess platform consisting of a UCI engine written in C and a graphical interface built in Python/PyQt5.


Some of you may know our previous projects:
- **PlayChessGate** (playchessgate.com) — historical player emulation
- **Pioneer 2 Chess** (play.pioneer2chess.com) — recreation of the Botvinnik Soviet chess computer system

LINEACHESS is a different kind of project. It started as an engine development exercise and grew into a full GUI application. It is of course not as full blown as Arena, Fritz or Shredder , but offers hands-on functionality for playing vs the engine or setting up enigne matches.

The Engine

The engine is written in C, single-threaded, and plays at approximately 2,535 Elo on our test hardware. It implements:

- Negamax with PVS and aspiration windows
- Null move pruning, LMR, reverse futility pruning, razoring, probcut, singular extensions
- Magic bitboard move generation
- Transposition table (configurable up to 2 GB)
- Static exchange evaluation for move ordering and pruning
- Tapered evaluation with pawn hash caching
- Polyglot opening book support

The evaluation covers material, piece-square tables, pawn structure (passed/isolated/doubled/backward/connected pawns), mobility, king safety (attack counting model), outposts, bishop pair, rook activity, threats, and endgame scaling for drawish positions.

Two Evaluation Styles

The program dose not have the pesonality layer emulaiton module form Chessgate or the Soviet move commentary fromm Pioneer 2. but we wanted to experiment with another way of transmitting human expert knowledge into the playing style for this project:

The engine offers two selectable piece-square table sets via the UCI `Style` option:

- **PeSTO** — the well-known hand-tuned baseline tables
- **Linear** — derived from the statistical analysis of 37,457 games played by all 16 undisputed World Chess Champions (Steinitz through Carlsen), with equal weight per champion

Both are scaled to the same signal strength. The Linear tables were generated by accumulating piece-placement frequencies per champion, averaging with equal 1/16th weight, and scaling each piece type to match PeSTO's peak magnitude. The resulting tables show different positional preferences: for example, the Linear knight table penalises rim squares less harshly and values some non-classical outpost squares more than PeSTO does.

In head-to-head testing at rapid time controls, Linear scored 4-2 against PeSTO, though both achieve approximately the same overall strength.

The GUI

The interface is a standalone application (no browser, no Electron). Features include:

- 7 difficulty levels (depth-limited, ~800 to ~2,535 Elo)
- 12 time control presets (bullet through classical) plus unlimited and fixed time-per-move
- Live engine analysis with automatic position tracking
- Engine-vs-engine matches and round-robin tournaments with live crosstable
- Dual engine output during matches (both engines' analysis visible simultaneously)
- PGN import/export with annotation support (comments and NAG symbols)
- ECO opening classification (3,688 openings from the Lichess database)
- Opening book display with move statistics (percentage and occurrence count)
- Position setup via FEN with preset endgame positions
- 4 piece sets (Classic/cburnett, Merida, Alpha, Cardinal)
- 5 board colour themes, 4 board backgrounds
- 15 interface languages with live switching
- External engine support — load any UCI engine (Stockfish, Komodo, etc.)
- Font size controls on every panel
- Resizable layout with collapsible panels


**Windows installer** (33 MB, no Python required): [https://drive.google.com/drive/folders/ ... sp=sharing]

The installer includes the engine, GUI, opening book, ECO database, all piece sets, and documentation.

Technical Details

- Engine: ~3,500 lines of C
- GUI: ~6,000 lines of Python (PyQt5)
- Opening book: Polyglot format, compiled from World Champion games
- Requires: Windows 10 or later

Feedback, bug reports, and test games are welcome. I hope you have fun with the progam.
Arne

[cpeters]

Hello Arne!

Code: Select all

- GUI: ~6,000 lines of Python (PyQt5)

1. I'd very much like to test it (on Linux) as it sounds cross-platformish, but the project is windows-only?
2. Probably it isn't free and open source?
2. What license (Qt5-things mixed with your software) did you choose?

greetings

[Chessgate]

Hello !

Yes it is built on windows but our other products like the pioneeer chess computer also run on linux, i have not tested for this one particular product since i am a windows native kind of guy (sorry)
everything is wrapped in the installer all libraries and dependencies. It is absolutely free.

I did just notice that i forgot to include a takeback button during gameplay though (duh!) so ill gett that tone in and hten update the upload link.

Best regards

Arne

[Chessgate]

Ok ,

I fixed the takeback button in the GUI . And also discovered that our "Linear" PST Tables were not correctly weighted! So ifixed this as well .


The "Linear" version of Lineachess engine somehow now plays very.... entertaining. I decided to leave it as is. It looks like it unleashed some crazy attack mode.
https://drive.google.com/file/d/1QvAHfr ... p=sharing

Best regards

Arne

[Tibono]

Hello Arne,
I watched a couple of games in Linear mode (before the tables fixing) and I was rather impressed by the aggressive way of play.
Now I am keen on using the updated weights!
Well done
Eric

[Elorejano]

Hi. How can I set the parameters for each engine? Ej. Threads, hash, books
Thanks in advance

[Chessgate]

Hi. How can I set the parameters for each engine? Ej. Threads, hash, books
Thanks in advance

Hi

I have added your requested functionality to the product which you can now download at



This being said it s freshly built so there could be some minor glitches, I have had no time to test it all in detail since I am also running the pipelines for adding Petrosian, Alekhine, Collle, Spassky etc... to www.playchessgate.com .

So it works with .bin opening book formats threads, hash size can be slected as well. But is is not a Chess Ferrari Interface, more like Lada covering the essentials.

Best regards


Arne

[ehenkes]

Great tool! I like it.

But there seems to be a weakness in the engine. I played against it at 1800 Elo with 30 minutes each.

In this position the engine (black) blundered heavily:
8/8/R3pkp1/6p1/3P2Pp/4PK1P/1r3P2/8 b - - 1 43
...Ra2 <-- Blunder!!

PS: I have a request: Would it be possible to move the pieces slowly? (smooth movement)

[Sylwy]

Beautiful achievement. Congratulations!

[Chessgate]

Great tool! I like it.

But there seems to be a weakness in the engine. I played against it at 1800 Elo with 30 minutes each.

In this position the engine (black) blundered heavily:
8/8/R3pkp1/6p1/3P2Pp/4PK1P/1r3P2/8 b - - 1 43
...Ra2 <-- Blunder!!

PS: I have a request: Would it be possible to move the pieces slowly? (smooth movement)

Hi !
Thank you for the kind words. I could unfortunately not reproduce the engine mistake with the fen you provided at the level you indicated . But I used the Pesto table version of the Lineachess engine at 1800 and 30 min per game.


But there is also good news: You cannow download the new relase of LINEACHESS at :


What's new in 2.01:

Dark mode toggle (View > Dark Mode)
Board zoom (mouse scroll + tiny −/+ controls)
Piece glide animation for engine moves (duration scales with time control)
"Out of book" status message
Buy Me a Coffee link in About
Toolbar spacing fix
All previous fixes (takeback, Hash/Threads/Book config, FEN positions, etc.)

Best regards

Arne