Daily Sudoku Challenge — 2026-05-15 (Hard) — Level 4
Warm up with the daily grid. Logic-only — no guessing required, just patience and pattern recognition.
| 9 | 1 | · | 4 | 5 | · | 8 | 7 | 3 |
| · | 7 | · | · | · | 3 | · | 4 | 1 |
| · | 4 | 5 | · | · | 1 | 9 | · | · |
| 4 | 8 | 1 | 6 | 3 | 9 | 7 | 2 | 5 |
| · | · | · | · | · | · | 4 | · | 8 |
| 7 | · | · | · | · | · | 1 | 9 | · |
| 5 | · | · | · | 9 | 6 | · | · | · |
| · | 2 | 7 | · | 8 | 4 | 6 | · | · |
| · | 9 | 8 | 7 | · | 5 | · | · | · |
Solving tips
- Scan rows, columns, and boxes for the most-frequent digit first.
- Pencil-mark candidates only when single-cell scanning stalls.
- Look for naked pairs in tight rows to eliminate options elsewhere.