Golden Nugget Sudoku — Play It Online, With the Full Solution

Updated 15 October 2026

Golden Nugget is a 21-clue sudoku posted to the Sudoku Players’ Forum as an open challenge, built to resist logical solving for as long as possible. It is commonly rated at SE 11.9, level with Everest at the top of the scale. Play the original grid below in your browser or in the app, print it, and follow the engine’s full solution further down.

Clues

21

Published SE rating

SE 11.9

Suuudokuuu rater

8.5+, past every implemented technique

Play Golden Nugget in the appPrint Golden Nugget — PDF with the solution

Where Golden Nugget comes from

Golden Nugget was not a newspaper puzzle. It came out of the forum where the people who write sudoku rating programs compare their hardest finds, and it was posted there as a challenge for solvers to work through. Its reputation comes from that community rather than from publicity, which is why it is less famous than AI Escargot and considerably harder.

Source: Sudoku Players’ Forum, “Golden Nugget challenge”. The SE figure is the published rating the Infinity corpus carries, not a Suuudokuuu measurement, and at this height different raters disagree by several tenths. The other record grids are on the hardest sudoku puzzles page.

The Golden Nugget solution, step by step

Suuudokuuu’s source-available engine solves Golden Nugget in 103 steps, reaching for the cheapest technique that still makes progress, exactly as it does when it rates a puzzle. 14 of those steps are forcing chains: the engine assumes a candidate, follows its consequences until something breaks, and removes the assumption. At 2 points even that runs dry — no technique the engine implements moves the grid — and the walkthrough says so, fills the cell with the fewest candidates from the verified solution, and carries on with logic from there. Every other step is a named deduction you can check by hand.

Along the way the walkthrough uses Full House, Naked Single, Hidden Single, Pointing Pair, Naked Pair, Finned X-Wing, Finned Swordfish, Sashimi X-Wing, W-Wing, AIC and Nishio Forcing Chain.

Where the engine has to fill a cell from the solution, its chains have run out of reach. That is the honest signature of an SE 11.9 grid: the deductions it needs are longer and more nested than a cell forcing chain of the kind the engine implements.