Articles
How to solve, faster.
Plain-language guides to the techniques real solvers use — illustrated, no jargon, no listicles.
May 23, 2026 · 5 min read · technique · beginner
The 45 rule: the first killer sudoku technique to learn
Every row, column, and 3×3 box of a sudoku adds up to 45. That single fact unlocks half the deductions you'll ever make in killer sudoku. Here's how to use it.
May 22, 2026 · 6 min read · technique · reference
Killer sudoku cage combinations: the complete cheat sheet
When a cage sum and the number of cells lock the contents to a single set of digits, you've found a forced combination. Here's the full table — every cage size, every sum, every digit set you'll ever need.
May 21, 2026 · 6 min read · technique · intermediate
Naked pairs, hidden pairs: the two techniques every solver should master
Naked and hidden pairs eliminate candidates without needing a single placement. Master them once and every sudoku — classic or killer — gets noticeably faster.