New engine releases & news H1 2026

[Elorejano]

Hi, Graham.
FireFly (if i remember ) needs some files that ar absent. Like an ini file, openings books etc
Do you have those ones?

It is a UCI engine, so the options will become available when loading it.

Its an XBOARD/uci engine, so those xboard files are needed. Im not use Uci protocol. Im using uci engines with polyglot under winboard

It requires a file named FireFlyStart.txt. The contents of that file as I use it is as follows:

egtbpath F:\Sakk\TB
poshash 256MB
pawnhash 16MB
*ignoreucihash
*usebitbase

Thanks, Gabor.
And the opening book? If im remember well, FireFly use its own format

[DreamerExx]

Ember 1.1.0 has been released . What's improved?
1. My personal NNUE (100SB) trained by me
2. A huge number of bugs have been fixed compared to 1.0.0
3. The Elo fluctuates around 2850-2950 according to my calculations (1.0.0 was approximately 2750)
Download: https://github.com/ExxDreamerCode/Ember ... tag/V1.1.0

[NathanDrake]

Triumviratus 5.0 Released
https://github.com/Tors3/Triumviratus/releases/tag/v5.0

• Evaluation: NNUE, SFNNv13 architecture (Full_Threats + HalfKAv2_hm, threat-aware).
• Network: Own-lineage nn-rubicon-alea-v1, trained from scratch (no Stockfish network seed) using nnue-pytorch.
  • Stage 1: Stockfish 5000-node data (λ = 1.0 → 0.75).
  • Stage 2: Leela self-play (λ = 0.74, fixed).
• Search: Original SPSA-tuned alpha-beta search, Lazy SMP, Syzygy tablebases.
• Strength: Approximately +50 Elo over v4.2 (internal testing, 20+0.2).

I know 4.2 is still being tested, apologies for the overlap, but 5.0 was ready and I didn't want to sit on it.

[cc2150dx]

PlentyChess 8.0.0

- Introduction of the new threat inputs NNUE architecture, which has since been introduced in many other top engines (including Stockfish, Reckless and others). As of late, the NNUE additionally has pawn-pair inputs
- Many speedups to make the NNUE architecture changes viable
- Greatly improved search logic, pushing the concept of fractional depth further to more heuristics
- SMP improvements: Sharing correction histories between threads and tuning under multithreaded conditions
- Proper NUMA handling on linux
- General improvements to the source code

https://github.com/Yoshie2000/PlentyChe ... g/b-v8.0.0

[vihaa]

Hi,

I am pleased to announce the public release of my UCI chess engine MagicTree 3.2, written in C++.

Download / website: https://magictree.netlify.app/

MagicTree is a 64-bit Windows UCI engine. It is a classical handcrafted-evaluation engine, with no neural network, no NNUE file, and no external evaluation file included.

The engine uses bitboards, BMI2/PEXT-based sliding attack generation, alpha-beta / PVS search, iterative deepening, transposition tables, move-ordering heuristics, pruning, and a tapered handcrafted evaluation.

Important requirement: MagicTree 3.2 requires a 64-bit Windows system with a CPU supporting BMI2/PEXT instructions. On older CPUs without BMI2/PEXT support, this build may fail to start.

Estimated strength: ~2725 blitz, this is a private-test estimate until the engine receives more external testing.

Current limitations:
- Windows x64 only
- BMI2/PEXT-capable CPU required
- No opening book included
- No Syzygy/tablebase support included
- No NNUE or neural-network file included
- Single-threaded release

I have tested the engine mainly under Windows x64 in UCI-compatible GUIs. I would be grateful for any bug reports, stability issues, GUI compatibility feedback, tournament results, or suggestions for improvement.

Looking forward to seeing how MagicTree performs in external testing.

Regards,
Vikrant

[Steve Maughan]

I'm pleased to announce the release of Juggernaut 2.0, a UCI chess engine for Windows (64-bit) written in Delphi / Object Pascal. It is a bitboard engine, with Lazy SMP multi-threading and a relatively simple PeSTO evaluation. Juggernaut 2.0 is rated at approximately 2750 Elo — around 700 Elo stronger than version 1.01.

Stability has been the top priority
More than anything else, this release focused on stability. A lot of effort has gone into making Juggernaut robust — hardened UCI handling, defensive error handling in the search, and a great deal of testing — so that it runs through long matches and tournaments without crashing, hanging, or losing on time. This was the number one goal for 2.0.

Very fast time controls
Juggernaut plays reliably at 0.2 + 0.002 — that is, 0.2 seconds base plus a 0.002 second increment per move, the fastest time control FastChess will run — without flagging. A fair amount of work went into the time management and search dispatch to make this dependable.

What's new since 1.0
Version 1.0 was a fairly basic engine. Juggernaut 2.0 adds the standard set of modern search techniques, including:

• Null-move pruning
• Late move reductions and late move pruning
• Reverse futility and futility pruning
• Singular, check and recapture extensions
• Internal iterative reductions
• Mate-distance pruning
• Improved move ordering: MVV-LVA with SEE, killers, counter-moves, and butterfly + continuation history

Together these account for most of the strength gain over version 1, and make Juggernaut quite good at tactics.

Other features

• User-selectable opening book — Polyglot books can be chosen and configured through UCI options, including in-memory loading and adjustable book randomness.
• Tidy mate reporting — once a forced mate is found, Juggernaut only sends a new principal variation if it finds a shorter mate.
• Chess960 and MultiPV support.

Also released: Juggernaut 1.01
I'm also releasing Juggernaut 1.01. This is a bug-fix release of the original 1.0 — there are no material strength changes from 1.0 (2030 elo) — but, like 2.0, it now plays correctly at the same ultra-fast time controls (0.2 + 0.002).

Downloads
Juggernaut 2.0: https://bit.ly/4arRrbv
Juggernaut 1.01: https://bit.ly/4eAMT52

Feedback and bug reports are very welcome.

[DreamerExx]

Ember 1.1.1 released!
Elo: 2850-2950
https://github.com/ExxDreamerCode/Ember ... tag/V1.1.1

[NathanDrake]

​Triumviratus 5.1
​Strength vs 5.0

• +64.7 ± 7.6 Elo (2000 games, 20+0.2, AVX2, same network).

​Changelog

• Search patches (+26 Elo): Threat-indexed quiet history, refined TT-cutoff, SPSA-tuned singular extensions.
• NPS & Perf optimizations (+26 to +42 Elo): Lazy NNUE-mirror apply (deferred computation) and PGO build flags.
• Display-only eval normalization (+1.00 cp ≈ 50% win probability). Search and TT remain untouched.
• Strict UCI compliance (silent startup, no ASCII banner).
• Two-level TT, hindsight extensions, faster SEE accumulators, re-tuned time management.

​vs. External Engines

• Pawnocchio 1.9.1: Even at 60+0.6 (+2.6 ± 7.5 Elo). Small edge at 20+0.2 (+9.6 ± 12.9 Elo).
• Berserk 14: -25.9 ± 18.1 Elo (25+0.25) (Before the NPS patches).

​Downloads
AVX2 and AVX-512 builds available on GitHub. Two variants provided: Standard (for normal play) and Development (exposes all internal tuning parameters as UCI options).
​Download on GitHub

[DreamerExx]

Ember 1.1.2 released!
Compared to version 1.1.1, a very serious bug was fixed where, instead of forcing a threefold repetition, the engine might make an incredibly stupid blunder and lose a move; this version is stable and offers a +50–70 Elo improvement over the previous engine.
https://github.com/ExxDreamerCode/Ember ... tag/V1.1.2

[cjug74]

Feedback and bug reports are very welcome.

Hello Steve,

I've noticed that, on every blitz game, Juggernaut 2.0 consumes almost all time in a move until it has only 3 seconds left, then it makes the move and all subsequent moves it plays almost instantly. The move that consumes almost all time is normally during middlegame.

I've only tested it on Arena GUI, blitz 3/2 and 5 no increment.