Easy, medium, hard and expert Sudoku: what's the difference?
Updated
You finish an Easy puzzle and a Hard one and they do not feel like a count of empty squares. They feel like different lessons. Easy, Medium, Hard, and Expert are the hardest step a puzzle needs, not how many digits you were given. Two puzzles with the same number of givens can sit in different grades. Fewer givens do not automatically mean Expert.
This page is the definition Calmtile’s grader uses. It matches the technique ladder in the solver. There is no separate tier that requires guessing.
The four grades
| Grade | Page | Hardest technique the ladder used |
|---|---|---|
| Easy | Easy | Naked single or hidden single |
| Medium | Medium | A pair, or pointing / box-line |
| Hard | Hard | A triple: three cells locked to three digits, or three digits locked to three cells |
| Expert | Expert | X-Wing, Swordfish, or XY-Wing |
A triple has no article of its own. The sentence in the Hard row is the definition. Swordfish and XY-Wing are names in the Expert row. Their steps are not taught here. X-Wing is the Expert lesson that has a page.
The Chinese names for the same four grades are 简单, 中等, 困难, and 专家. The lessons do not change with the language.
What is not a grade
Fewer givens do not automatically mean a harder puzzle. Here, the grade comes from the highest technique the ladder uses to finish the grid. A search may keep an internal limit on how many clues to leave. That limit is not a grade, and it is not printed on the puzzle.
Notes are not a grade. Pencil marks are yours to write. An automatic candidate list is a different tool. The current play screen provides manual Notes, off by default. Using them does not move the puzzle. Leaving them off does not either. The grade was fixed when the puzzle was built, from the steps above.
Hi8 describes its own clue ranges on Hi8 Sudoku. Those ranges are Hi8’s standard.
Names that do not line up
Other sites use labels such as Evil and Impossible. Chinese pages elsewhere say 入门, 初级, 中级, 高级, and 骨灰. Those words do not match each other, and they do not match this table, if you try to line them up by name. What you can compare is the technique a puzzle actually requires.
The labels vary from site to site. To compare two puzzles, look at the techniques needed to solve them. Calmtile’s Expert tier may use X-Wing, Swordfish, or XY-Wing. There is no separate tier that requires guessing.
What never gets a grade
If the ladder cannot finish a puzzle, the puzzle has no grade. It is not published as Easy, Medium, Hard, or Expert. Guessing is not a missing step on the ladder. A puzzle’s grade describes its solving techniques. Whether you used a reveal is a separate fact about how you finished it.
Next
For now, you can try a practice puzzle on the Sudoku page, or keep the check order beside you.