Sudoku 16x16: Giant Sudoku

The rule is the one you know: every row, column and box holds each number once. What changes is the scale. There is more to scan, more notes to keep, and the satisfaction of finishing lasts a lot longer.

How to play

Click a square, then a number on the pad. On a keyboard, numbers 1 to 9 work as usual. For 10 to 16, press 1 and then the second number straight after, so 1 then 6 enters 16. Use the arrow keys to move around.

Scan one number at a time

On a big grid it is easy to lose your place. Pick one number and go box by box looking for squares where it must go. Selecting a square lights up every copy of the same number, which makes this much faster.

Use notes early

With sixteen options per square, it is hard to hold everything in your head. Once scanning slows down, switch Notes on for the box you are working on. The notes grid in each square is laid out 4 by 4, so the numbers always sit in the same place.

Take breaks

A 16 by 16 puzzle is a long game. The timer stops when you pause or switch tabs, and your progress is saved in your browser, so you can come back to it later the same day or next week.

The three levels

Easy	About 140 of the 256 squares filled. Mostly scanning.
Medium	About 120. Notes become useful in the emptier boxes.
Hard	About 105. Pairs and pointing pairs needed, and plenty of patience.

If you are new to big grids, try classic 9 by 9 Sudoku on Hard first. The techniques in our strategy guide all work on 16 by 16.

Questions people ask

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