Meet the Five New Master Levels

If you’ve ever solved a Master puzzle on TheSudoku and thought “that was brutal” — or, conversely, “that was surprisingly manageable” — you weren’t imagining things. Until now, “Master” was a single bucket containing puzzles of wildly different difficulty. Today we’re splitting it into five clearly defined tiers: Young, Adept, Veteran, Fiendish, and Supreme.

Why split Master?

Difficulty matters most precisely at the Master level, because this is where Sudoku game becomes a whole spectrum. In the lower tiers the spread is narrow — an Easy puzzle and another Easy puzzle don’t differ too much. But above Expert, the landscape explodes: a puzzle rated 4.x asks for a single X-Wing and SkyScraper, while an 8.x demands several forcing chains, advanced fish and multi-digit eliminations woven together. Both used to sit under the same “Master” label.

In practice that meant a random Master game could hand you a puzzle that requires one advanced technique — or a monster that needs a long chain of them. For most players the difference between ER 4 and ER 8 is the difference between a satisfying challenge and a wall. There was no way to know which you’d get before you started, and no way to gradually work your way up.

Now you can. Each tier corresponds to a precise difficulty band, measured the same way the hardcore Sudoku community has measured puzzles for two decades: the Sudoku Explainer rating, or SE — often abbreviated ER (Explainer Rating) on forums.

What is the SE rating?

Sudoku Explainer is a program written by Nicolas Juillerat in the mid-2000s. It was one of the first tools that could solve a Sudoku the way a human does — not by brute-force backtracking, but by applying a catalog of logical techniques in order of increasing sophistication.

Its famous output is a difficulty score. The idea is simple and elegant:

• Each solving technique has a difficulty weight — a naked single is cheap, an X-Wing costs more, a forcing chain costs a lot.
• SE solves the puzzle step by step, and the rating is essentially determined by the hardest technique required, plus how much work the puzzle demands overall.
• The result is a number roughly between 1.0 and 11.9. A newspaper “easy” puzzle sits around 1.2–2.0; something that requires X-Wings lands near 3–4; puzzles above 7 enter serious “prove you actually know advanced techniques” territory; the infamous Easter Monster is rated 11.9.

Because the rating is produced by a solver rather than by marketing, it became the de facto standard among puzzle setters and solver communities. When people on forums say “this puzzle is an 8.5,” they almost always mean the SE rating. (Hodoku and other modern tools use the same scale.)

Our five Master tiers

Every puzzle in each tier was generated and then individually rated, so the label isn’t a guess — it’s a measurement:

• Young — SE 4.0–4.9: wings and simple coloring. A serious step past Expert, but logical throughout.
• Adept — SE 5.0–5.9: multi-digit patterns, XY-Wings, longer chains.
• Veteran — SE 6.0–6.9: multiple advanced techniques per puzzle; technique-chaining required.
• Fiendish — SE 7.0–7.9: deep inference, forcing chains, advanced fish. Solving one is an evening’s work.
• Supreme — SE 8.0–8.9: the top of our generator’s range. If you can do these consistently, forums await your Easter Monster attempts.

Each tier launched with 2,000 freshly generated, individually rated puzzles — 10,000 new Master grids in total.

How to play them

• Landscape header: the Master button is now split. The left side works exactly as before — a random puzzle from the whole Master pool. The arrow on the right opens the tier picker.
• New Game menu: same deal — Master gets a small arrow that opens a sub-view listing all five tiers.

A word of advice

Don’t start with Supreme. Seriously. SE ratings are calibrated against techniques, not time — a 4.x puzzle already expects you to spot patterns most casual players have never heard of. Pick Young, get a feel for what the rating means in practice, and climb from there. That’s the whole point of the split: Master is now a staircase instead of a cliff.

Happy solving — and when you finish a Supreme without a single hint, take a screenshot. You’ve earned it.