Suguru / How to play

How to play Suguru (Tectonic)

Suguru is a number puzzle on a grid that is split into shapes. You fill every cell with a number, and there is only one right answer. You never need to guess. Every step can be worked out. This page covers the rules and the first moves that get most puzzles going.

The rules

1. Fill each shape with the numbers 1 up to its size. A shape of three cells holds 1, 2 and 3, once each.
2. The same number may never touch itself. That includes diagonals, so every cell has up to 8 neighbours to check.
3. Each puzzle has exactly one solution, and logic alone will find it.

Your first moves

One-cell shapes are always 1

A shape with a single cell can only hold a 1. Write those in first.

Two-cell shapes hold 1 and 2

A shape with two cells holds a 1 and a 2. You may not know which way round yet, but you know the pair, and that is often enough to rule things out nearby.

A number rules itself out around it

Once a cell holds a number, none of the 8 cells around it can hold the same number. Cross that number off as an option in all of them.

The last number left

Take a shape of four cells where you have already placed 1, 2 and 4. The empty cell must be 3. Count what a shape still needs, and when only one number is missing, you know where it goes.

The only place left

Pick a number a shape still needs, then check each empty cell in that shape. If neighbouring numbers rule it out everywhere except one cell, it goes in that cell.

A cell that touches both cells of a two-cell shape

Say a two-cell shape holds a 1 and a 2, and an empty cell touches both of its cells. Whichever way round they end up, that cell sits next to a 1 and next to a 2. So it can be neither. Cross out 1 and 2 in it.

Stuck?

Suguru never needs a guess. If you cannot see a move, look for the shape with the fewest options left and work out what each of its cells can still be. Then check the cells around the numbers you already have. Somewhere on the board, one cell has only one option.

In the Suguru app, a hint names the technique and points at the cell. Next time you can spot it yourself.

Other names

In the Netherlands, Belgium and Germany the puzzle is usually called Tectonic. You may also find it as Number Blocks. It was invented by Naoki Inaba in Japan, and the rules are the same under every name.