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Killer Sudoku

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Killer sudoku puzzles are built from scratch and checked for a single valid solution — this takes a few seconds.

©2026 Luke Arrington

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Puzzle Generator

About this player

Killer sudoku has no starting digits at all — every cage's colored background and its small sum are the only clues. Fill every row, column, and 3×3 box with 1-9 exactly like classic sudoku, with the extra rule that the digits inside every cage must be all different and add up to that cage's printed sum. Use Import to paste in a puzzle exported from this site's generator, or open a link that already has one encoded in it. The Clue button uses a solving-technique engine that understands both ordinary sudoku logic and cage-specific reasoning (cage combinations, "innie/outie" sums, and more).

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How to Play

Killer sudoku combines classic sudoku with a layer of arithmetic. Here's everything you need to know.

🎯 The goal

Fill the 9×9 grid so every row, column, and 3×3 box contains the digits 1-9 exactly once — same as classic sudoku.

🧩 No starting digits

The grid starts completely blank — there are no given numbers. Instead, the only clues are the cages: the colored groups of cells you see on the board.

➕ Cage rules

Each cage has a small number printed in its top-left cell — that's the cage sum. The digits placed inside that cage must add up to exactly that number.
Every digit inside one cage must be different from the others in that cage — no repeats, even though a cage can stretch across multiple rows, columns, or 3×3 boxes.

🎨 Reading the board

Each color marks one cage. Neighboring cages always get different colors so it's easy to see where one ends and the next begins.
The thin grid lines are ordinary sudoku cell borders; the thick lines mark the 3×3 boxes, exactly like a classic puzzle.

💡 Getting started

Small cages with sums near the extremes are the fastest way in — a 2-cell cage summing to 3 can only be {1,2}; one summing to 17 can only be {8,9}.
Combine cage-sum logic with ordinary sudoku deduction — once a cage's possible digits are narrowed down, the row/column/box rules often pin down exactly which cell gets which digit.
Stuck? Tap Clue for a real hint from the built-in solver, or turn on Candidates to see every digit still possible in each cell.

Options

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Import a puzzle

Paste the code copied from Export on this page, or from a "Play this puzzle" link on the generator page.

Puzzle code

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