Hardest Sudoku — SE grade 6.5–7.4
SE grade 6.5 to 7.4
By The Hardest Sudoku Team · Last updated
TL;DR
Wings (XY-Wing) and larger fish (Swordfish) appear, and progress often depends on chaining one elimination into the next.
What is a SE grade 6.5–7.4 puzzle like?
Wings (XY-Wing) and larger fish (Swordfish) appear, and progress often depends on chaining one elimination into the next.
Which techniques does this band need?
What this band actually requires
We publish 166 puzzles in this band, and a full logical solve takes 69 steps on average. These are measured from our own solver, not estimated.
- · Naked Single — needed by 166 of 166
- · Hidden Single — needed by 166 of 166
- · Claiming (Locked Candidates) — needed by 97 of 166
- · Pointing (Locked Candidates) — needed by 163 of 166
- · Naked Pair — needed by 134 of 166
- · Hidden Pair — needed by 14 of 166
- · X-Wing — needed by 12 of 166
- · XY-Wing — needed by 35 of 166
- · Forcing Chain — needed by 166 of 166
Technique counts come from running our step-by-step solver over every published puzzle in the band.
Puzzles in this band
Where does this sit on the scale?
See the full ladder on the SE grade page. The hardest puzzles — the monsters — live at the top of the scale; meet them on What is the hardest Sudoku?
Play puzzles at this grade →