Suguru: rules, regions and solving techniques

Goal of the game

Fill every region with its required numbers while making sure equal digits never touch, even diagonally.

Rules

• A region of N cells contains the numbers 1 to N exactly once. Given digits never change.
• Two equal digits can never touch by an edge or a corner, even when they belong to different regions.
• Rows and columns have no uniqueness rule of their own: the same digit may appear again farther away as long as the region and adjacency rules are respected.

A simple example

1. A three-cell region already contains 1, so its two empty cells must be 2 and 3.
2. One of those cells touches a given 2 diagonally in another region.
3. That cell therefore cannot be 2, so it must be 3.
4. The final cell in the region becomes 2, provided its own neighbours allow it.

Useful first deductions

• For each empty cell, start with the numbers allowed by the size of its region.
• Remove numbers already used in the region and numbers present in any of the eight neighbouring cells.
• If only one candidate remains, the cell is solved. If a number has only one possible position inside a region, that position is also forced.
• If two cells in a region share exactly the same two candidates, those two values are reserved for those cells and can be removed elsewhere in the region.

Common mistakes

• Forgetting diagonals: adjacency includes corners as well as edges.
• Using the number range from a large region inside a smaller one.
• Applying Sudoku-style uniqueness to entire rows or columns.
• Checking only the region and forgetting neighbouring cells in other regions.

Controls

Select a cell and use the keypad, which is automatically limited to values that make sense for the size of that region.

Given digits cannot be changed. Draft lets you note candidates; turn it off to enter a final value. Clear or Backspace/Delete empties the selected cell. Undo reverts the latest change. Pause, Resume and Check are also available.

Difficulty

Easy, Medium and Hard are based on increasingly long chains of logical deduction. Expert may require comparing several possible lines of reasoning before one survives. Difficulty therefore depends not only on grid size, but on how many constraints must be combined.

FAQ

Is this guide free?

This guide and its interactive tutorial are free. Explore the rules here, then browse the game library.

How is Suguru different from Sudoku?

Suguru does not require uniqueness across a whole row or column. Its constraints come from the regions and the immediate neighbours around each cell.

What should I do if I cannot see a move?

Recalculate candidates cell by cell using the region and all eight neighbours. A value that has only one possible position left in a region is often the next deduction.