SELECT // LEVEL
挑一道谜题开始。
什么是 Hardest Sudoku？
What is Hardest Sudoku? Hardest Sudoku is a free web Sudoku trainer that goes up to the hardest puzzles ever rated. Every puzzle is measured on the objective SE grade scale — the difficulty is a number, not a marketing label. It reaches the legendary monster puzzles at the very top of that scale. Hints explain the next step; they never solve a cell for you. The tedious parts are handled for you, so you focus purely on the logic.
How is difficulty measured? SE grade is the difficulty number from Sudoku Explainer: the higher the grade, the more advanced the logic a puzzle demands. Easy puzzles sit near 1.0–2.0; the hardest monsters reach roughly 11.0 and above.