Mini sudoku 6×6 (hard)

This is hard mode on the 6×6 grid. The rules are unchanged — digits 1 to 6, once each per row, column and 2×3 block — but the starting clues are deliberately sparse. Very few cells fall at a glance, so you end up doing the real thing: "this column is missing two digits, but the block rules out one of them, so this cell must be a 3."

The reasoning used here is essentially the same as the core technique set for 9×9 sudoku. Because the board is smaller, each puzzle is short: a good fit for a commute or the last ten minutes before bed. Every grid is generated with a unique solution, so it is always solvable by deduction rather than luck, and Check highlights only the wrong digits so you can see exactly where your reasoning slipped.

If this feels steep, warm up on 6×6 easy or 4×4 easy. If it's falling quickly, make your full-size debut on the 9×9 easy sudoku, updated with 20 puzzles a day. Techniques live in how to play sudoku, all mini sizes on the mini sudoku page, and every level on the home page.