Killer Sudoku

Killer Sudoku: 200 original verified puzzles, clear candidate notes, undo and explained logical hints.

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Killer Sudoku gameplay preview

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About Killer Sudoku

Killer Sudoku combines placement and arithmetic. Connected cages have fixed totals and cannot repeat digits. A total narrows combinations, while rows, columns and boxes decide which combinations fit each position. Cage totals do not replace ordinary Sudoku rules.

How to begin

Use ordinary Sudoku units. Every connected cage has the indicated total and contains no repeated digits. Select an empty cell before choosing a digit. Given digits stay fixed. On a keyboard, use the arrow keys to move and 1–9 to fill; on a phone, use the digit buttons below the grid.

A two-cell cage totaling 3 contains 1 and 2, in some order. A cage totaling 10 does not make every sum-to-10 pair available: any digit excluded by a row, column or box is unavailable in that cell.

Turn possibilities into a reason

The cage assistant shows ordered compatible sequences using the current board. Its cell order is explicit. Filled digits count toward the target, and repeated cage digits are rejected.

A complete row, column or box totals 45. If fully enclosed cages account for 36, the remaining cells sum to 9. This arithmetic becomes useful only after checking which cages are wholly inside the unit.

Manual notes let you record candidates without committing to a value. The optional candidate tool is an explicit action, and Undo restores the notes it replaces. A hint first points to cells worth inspecting, then explains the supported logic, and reveals a conclusion only after another request.

Choose your own route through 200 puzzles

The fixed collection is sorted using the techniques and candidate bottlenecks in its logical solutions. Puzzle selection is open from the beginning, so experienced players can choose a later puzzle and newcomers can work through the guided order. These labels describe solver evidence; they are not claims about an independently measured human completion time.

Questions while you play

Does a highlighted conflict mean the stored answer is different?

No. A conflict marks a broken rule on the current board. A digit that is different from the eventual solution may remain unmarked while it breaks no visible constraint. You can change it, use Undo or restart safely.

Is the daily selection a new puzzle?

It is a consistent daily choice from the verified collection, marked as a selection or replay. It uses a separate date-specific save and does not add to the 200-puzzle count.

Can I leave and continue later?

This browser stores each puzzle separately. Reopening restores digits, notes and undo history when the save is valid. Use the game’s Export this puzzle save control before clearing browser data; import that file into the same puzzle and mode. If browser saving fails, the game says so and keeps the current board in this tab.

Learn with the original guide: Use the total and the current unit restrictions together.

How to play

Use ordinary Sudoku units. Every connected cage has the indicated total and contains no repeated digits.

  1. Select an empty cell, then choose a digit or switch Notes on.
  2. Ask for a gentle hint: attention first, proof next, then the conclusion only when you request it.
  3. Undo uncertain moves or pause. Every puzzle is open; daily selections use a separate save.
Controls & saving

Select a cell · 1–9 fill · N notes · arrows move · Delete erase · Ctrl/Cmd Z undo

Automatic saves belong to this browser and this game. Changing devices or clearing browser data does not transfer them. Use the game’s save tools for an exported backup.

A gentle starting point

A two-cell cage totaling 3 contains 1 and 2, in some order. A cage totaling 10 does not make every sum-to-10 pair available: any digit excluded by a row, column or box is unavailable in that cell.

Use the total and the current unit restrictions together.

Another visit, your own pace

Favorite this game to find it on your Favorites page. The daily center has three dated picks each day; your game progress stays separate from them.

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