Sudoku — hard (2026-06-05)

• Do pencil marks early—Hard puzzles often require elimination before placements appear.
• Look for constrained candidates and box-line interactions; avoid random guessing.
• Work systematically: after each change, re-check affected units for newly forced singles.

• Grid: 9 × 9
• Given cells: 27
• Empty cells: 54
• Starting density: fewer givens

Hard puzzles often start with fewer direct placements. With 27 givens, use pencil marks early and hunt for constrained rows/columns and box-line interactions.

Keep going with another puzzle:

• Try today’s other difficulties: Easy · Medium
• Previous days (Hard): Thu, Jun 4 · Wed, Jun 3 · Tue, Jun 2 · Mon, Jun 1 · Sun, May 31 · Sat, May 30 · Fri, May 29

How long does today’s Sudoku usually take?

Hard Sudoku can take 20+ minutes. With fewer direct placements, using pencil marks early helps.

What are the rules of Sudoku?

Fill the grid so each row, each column, and each 3×3 box contains the numbers 1 to 9 exactly once.

What’s the best first move today?

Start by scanning for rows, columns, or boxes that are nearly complete. With 27 givens, look for cells that have only one possible candidate.