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The lab

The wiki's open notebook: structural findings and named search experiments, each credited to the researcher who ran it and reproducible from source. One corner of the community's wider research.

pageUpdated 2026-07-10
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How the lab publishes

The editorial standard for this open notebook: how a piece of Eternity II research goes from unpublished work to a published page. What kind of contribution it is, whether it publishes, at what tier, and where it lives. One shared standard, built to scale to many authors.

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Experiments

The lab's named search experiments, one section per researcher. Each is a real run against Eternity II with its idea, its best board, and the questions it left open. Raphaël Anjou's notebook is here in full; the notebook is open to anyone else's.

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Single-core benchmark

Fifteen solvers, ours and our implementations of the community's two record backtrackers, each run once on ten corner-pinned variants of the official puzzle, single core, 60 seconds per run. The finding: node count is not score.

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Raphaël Anjou's experiments

A notebook of Eternity II search experiments, organised into the shared engines they run on, the combination pipelines that chase the score, three studies that take one search paradigm apart a decision at a time, and exact endgame solves. Each has its idea, its best board, and the questions it left open. The best reaches 463 of 480.

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Peter McGavin's engine

Peter McGavin's own C backtracker, the fastest raw solver the community has measured. Fetched from the mailing list, built on an M1, and run on the real Eternity II. His code, his algorithm; run and written up here.

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Joshua Blackwood's solver

Joshua Blackwood's open-source C# solver, the one that found the standing 470 record. Built and run here as he published it, then with the five official clues pinned. His code, his algorithm; run and written up here.

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Louis Verhaard's eii

Louis Verhaard's eii won the only prize the puzzle ever paid, but it shipped as a Windows binary with no source. What his method is, why the original will not run here, and where a faithful reimplementation of it lives.

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