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Free Killer Sudoku online — cages, sums, and pure logic

Killer Sudoku is standard Sudoku — fill every row, column, and 3×3 box with 1–9 — wrapped in an extra layer: the grid is divided into dotted "cages," each printed with a target sum, and the digits inside a cage must be distinct and add up to that sum. Classic Killer starts with no given numbers at all; the cages are the only clue. On Sukuro every board is freshly generated, verified to have exactly one solution, and playable instantly in your browser.

The way in is cage logic: a small cage has only a few possible digit sets (a 2-cell cage of 3 can only be 1+2; a 3-cell cage of 24 only 7+8+9), and every row, column, and box sums to 45, which lets you deduce cells that no single cage could. Sukuro gives you a cage-combination calculator, a coach that explains the next logical step in your language, a 1–100 difficulty ladder, eight languages, large-print and right-to-left support, and printable PDFs.

How to play Killer Sudoku

  1. Remember there are no givens — read each cage as the short list of distinct-digit combinations that reach its target sum.
  2. Place the forced cages first: small cages with a single possible combination hand you certain digits to build from.
  3. Use the 45 rule — each row, column, and box totals 45 — to pin "innie" cells where cages spill across a unit boundary.
  4. Once cages give you a foothold, finish with ordinary Sudoku logic (naked and hidden singles); use the cage calculator and Hint button when stuck.

Why play Killer Sudoku on Sukuro

Sukuro is built to teach the cage reasoning, not just check your grid: a complete cage-combination calculator, a coach that explains each next step (never a guess), and a 1–100 ladder graded by the techniques a puzzle actually needs. Accessibility is always free — large-print, high-contrast themes, full keyboard play, and right-to-left layout are never behind Premium.

Killer Sudoku FAQ

What is Killer Sudoku?
Killer Sudoku combines Sudoku with cages: alongside the usual row/column/box rule, the grid is split into cages whose cells must hold distinct digits adding up to a printed target sum. It usually starts with no given numbers.
Can a digit repeat inside a cage?
No. In standard Killer Sudoku the digits within a cage must all be different — that, plus the target sum, is what makes a cage solvable. (Digits can still repeat across different cages, subject to the normal Sudoku rules.)
Is Killer Sudoku on Sukuro free?
Yes — unlimited Killer Sudoku, all 100 levels, the cage-combination hints, and every language are free. Premium only adds an ad-free board, unlimited hints, and a live AI coach.

Learn Killer Sudoku cage strategy · Killer Cage Calculator · Rules