The Story of Luna CE

[Spunc595]

Luna started as a few hundred lines of JavaScript in December 2025 — my first ever attempt at a chess engine. A week later I rewrote it in Rust, and then kept rewriting it, over and over, sometimes several versions in a single sitting, for months.

Along the way I trained my first NNUE net myself, using nothing but a laptop — it was too weak to be useful, but it was a start. Much later, in July 2026, I made a real mess of things with an AI assistant: I pasted unreviewed AI-generated cleanup work straight to GitHub, and it showed. I cleaned that up and, around the same time, rebuilt the engine's whole NNUE implementation from scratch with a new accumulator and a properly licensed network.

What started as a hobby project with no version control discipline at all is, nine months and something like 190 saved versions later, a UCI engine with multi-threaded search and a rewritten NNUE.

I put the whole thing in writing: HISTORY.md — an honest account of that path, including the AI-assisted mess I made and owned publicly at the time.

And since a written account is still just my word for it, I also published every saved version along the way, raw, as its own repository: Luna-CE-History-Archive. Each folder is committed individually, dated to match when I actually saved it rather than when I published it today — from original file timestamps where they survived intact, or from my own folder-naming where a later backup copy had overwritten the file metadata. The method is documented in that repo's README, and I still have the original folders on my own disk with their original timestamps if anyone wants to look closer than what a git log can show.

Also shipping two new releases while I was at it: v3.0.0 (the NNUE rewrite) and v3.1.0 (same base, plus Lazy SMP multi-threading) — both on the releases page, with Android builds attached.

Daniele

[Joseph]

What is the elo rating of this engine?

Joseph.

[Graham Banks]

What is the elo rating of this engine?

Joseph.

Around 2300-2450 from memory.

[Joseph]

What is the elo rating of this engine?

Joseph.

Around 2300-2450 from memory.

Thanks Grahama Banks

[Spunc595]

Luna CE's elo on lichess are: Bullet 2349; Blitz 2340; Rapid 2387; Standard 2364.

[mephisto]

Hi Daniele
Could you please advise which Android chess program can run your chess engine as Chess for Android can't.
Thanks
Bryan

[Joseph]

Hi Daniele
Could you please advise which Android chess program can run your chess engine as Chess for Android can't.
Thanks
Bryan

DroidFish

[mephisto]

Thanks