Sudoku Paradise Benchmark

Hardest Sudoku Compared: AI Escargot vs. Everest vs. Golden Nugget

Three enduring Sudoku Monsters were submitted to the same logic-first solver library. All three were solved without blind Trial & Error, but each resisted in a remarkably different way.

By Andy Beaudry · Published August 14, 2026 · Expanded August 20, 2026

Three Monsters, three kinds of difficulty

AI Escargot, created by Arto Inkala in 2006; the Golden Nugget by tarek in 2007; and Arto Inkala’s 2012 puzzle known as Everest or AI Maze all appear in discussions of the world’s hardest Sudoku. AI Escargot and the 2012 Inkala puzzle are sometimes confused because both were promoted as the world’s hardest. They are separate grids with very different logical personalities.

The current verification runs used the evolving Sudoku Paradise Human Solver and its 54 human-style methods. Every puzzle received an Insane rating. Every puzzle was logic-solved. None required blind Trial & Error.

*Times are machine-dependent and are not universal performance claims. Logical-action counts describe the recorded path produced by this solver deck and dispatch order; they are not interchangeable with human minutes.

What the benchmark does—and does not—prove

The Sudoku Paradise deduction solvers do not use brute force or derive deductions from a stored solution. Candidate eliminations are produced by identifiable logical strategies, and the final log records a logical narrative rather than an opaque computational answer.

AI Escargot

AI Escargot is comparatively compact, but several critical deductions must be proven before it yields. In the current run, ALS-XZ, Conjugate Contradiction Scout, SET Equivalence, a Finned Swordfish, and several Locked Candidate interactions all contributed to the break-in.

The Golden Nugget

The Golden Nugget produced fewer recorded actions than the other two current runs, but that number understates its human hostility. It demands high-level relationships almost immediately and remains densely resistant.

Everest, also called AI Maze

Everest produced the largest logical record—149 actions—but completed in the shortest machine time. That apparent contradiction is the most instructive result in the comparison.

SET changed the logical landscape

The latest important addition to the solver deck was Set Equivalence Theory. Removing its former cap of 12 eliminations allowed Human Solver to recognize the full value of the pattern on Everest. SET removed 22 candidates and displaced 21 steps previously attributed to Forcing Nets.

That result did more than improve the running time. It demonstrated that the “Three Easy Steps” approach to Everest—SET, focused contradiction, and solving to the end through cascaded Singles—provides a genuine strategic advantage. Everest did not become a different puzzle. The available logical understanding changed.

So which puzzle is hardest?

“Hardest” can mean the most logical actions, the greatest number of advanced strategies, the most contradiction proofs, the fewest accessible openings, or the puzzle that forces an experienced human to request the most assistance. Those measurements do not always choose the same winner.

The larger lesson is that no “hardest Sudoku” title is permanent. Difficulty is partly a property of the puzzle and partly a measure of the strategies we have not yet learned to see.

Try the evidence yourself

1. Copy one of the 81-character puzzle strings above.
2. Open Sudoku Paradise and choose the Custom Puzzle option.
3. Paste the grid, analyze it, and work as far as your own logic carries you.
4. Request a Hint only when you need a reproducible continuation.

This comparison was written from the Sudoku Paradise verification audits and Andy Beaudry’s manual field tests. The solver library was actively evolving during the study, so the latest detailed audits supersede the shorter action counts in the original forum opening. Solver timing varies by machine; the repeatable evidence is the recorded logical path.