Suguru Solver, Step by Step
Drawing: drag across the squares of one region, then the next; a tap makes a one-square region. Numbers: tap a square, then its number.
How to use the suguru solver
Set the width and height, then draw each region by dragging across its squares. Switch to Type numbers and enter the given numbers. Press Explain the next step: the solver fills in the number that is certain, or crosses out the pencil marks that cannot be, highlights what the reason is about, and says why. Show the answer fills the grid at once and checks the solution is the only one. The puzzle is also called Tectonic, or Number Blocks.
The rules of suguru
The grid is divided into regions of one to five squares, sometimes more. A region of N squares holds each number from 1 to N once. The same number may never appear in two squares that touch, not side by side and not at a corner, even when they are in different regions.
How to solve suguru, step by step
Start with the small regions. A region of one square is a 1, and a region of two holds 1 and 2. Use the touching rule. Each number rules itself out of the eight squares around it, so look for squares with only one number left, and for numbers with only one place left in their region. Look past the region wall. When every place left for a number in a region touches the same outside square, that square cannot be that number. Find pairs. Two squares in a region that can only be the same two numbers hold both of them. When those run out, the solver tries a number and keeps it only if it does not lead to a dead end.
How it was checked
The solver was run on all 150 puzzles of the daily suguru. It found each stored answer and found it to be the only one, and every step it explained was checked against those answers: it never placed a wrong number or ruled out a right one. It was also run on 24 larger puzzles up to 10 by 10 that need the harder moves.
More logic puzzles
There is a new daily suguru every day. The sudoku solver and the KenKen solver explain their steps the same way. For a puzzle you hold in your hands, see our brain teasers. There are more solvers on the puzzle tools page.
Frequently Asked Questions
How do you solve a suguru?
Start with the small regions: a one-square region is a 1 and a two-square region holds 1 and 2. Each number rules itself out of the eight squares around it, so look for squares with one number left and numbers with one place left in their region. When every place for a number touches the same outside square, that square cannot be that number.
What are the rules of suguru?
A region of N squares holds each number from 1 to N once, and the same number never appears in two squares that touch, side by side or at a corner, even across regions.
Is suguru the same as Tectonic?
Yes. Suguru is the Japanese name; the same puzzle is published as Tectonic and as Number Blocks.
Can the same number touch diagonally in suguru?
No. Two equal numbers may not touch at all, so a number rules itself out of all eight squares around it.
Does every suguru have one solution?
A well-made one does. The solver checks, and says if the grid you entered allows more than one.