What are the extra groups?

Nine groups, one for each position in a box. Each holds the cell in that position from all nine boxes.

Which cells are shaded?

The top-left cell of every box, as an example of one group.

Sudoku where all cells in the same spot of their box must also differ: nine extra groups of nine.

Disjoint Sudoku

0% · Getting ready

A real run of the game, recorded with captions and no sound.

Fill the grid so every row, column and 3 by 3 box holds 1 to 9 once.
In this variant, the nine top-left cells of the boxes must all differ, and so must the nine top-middle cells, and so on for every spot in a box. The top-left spots are shaded.
Tap a cell, then a number. Notes mode lets you pencil in candidates. Conflicts show in red as you play.
Pick Daily for today's puzzle, the same for everyone, or Easy and Hard for fresh ones. Your time is saved when you finish.

Controls: mouse, touch or keyboard. Made by CalcoTools.

Think of each box as a 3 by 3 pattern. A digit has to take a different spot in every box.
If a digit is in the top-left of one box, it cannot be top-left in any other.
Use the shaded cells as a check: they must hold 1 to 9 once each.
A digit that fits only one spot in a box often decides another box too.

What are the extra groups?: Nine groups, one for each position in a box. Each holds the cell in that position from all nine boxes.
Which cells are shaded?: The top-left cell of every box, as an example of one group.
Is the daily the same for everyone?: Yes, on the same UTC day.