Medium Sudoku X
Medium Sudoku X — around 34 givens. The diagonals start carrying their weight: deductions that need three units of row/column/box info on a Classic puzzle only need two units plus a diagonal here.
Medium puzzles start to need basic pencil-mark techniques: naked pairs (two cells in a unit that can only be two specific digits) and hidden singles across wider units. A typical solve runs 7–15 minutes.
Free downloadable Sudoku puzzles across four variants — Classic, Killer, Sudoku X, and Hyper — with answer keys on the back pages. No accounts, no colour ink.