What is suguru?
Suguru is a number puzzle played on a grid that is cut into small regions, like a map of tiny countries. Each region has between one and five cells, and your job is to fill it with the numbers from 1 up to its size. A region of three cells gets 1, 2 and 3. A region of five cells gets 1 to 5. On top of that comes the rule that gives the puzzle its character: the same number may never touch itself, in any of the eight directions around a cell.
You will also find it under the names Tectonic and Number Blocks. The rules are identical whatever the name on the page. Suguru is credited to the Japanese designer Naoki Inaba, and it has since spread through puzzle magazines and apps all over Europe.
The appeal is that the rules fit in two sentences and you never need to guess. Every number follows from the ones around it, and each one you place makes the next cells easier to read.
How to play suguru online here
Tap a cell, then tap a number on the pad. On a computer the pad sits beside the board, and on a phone it sits below. You can also play with the keyboard: arrow keys to move, 1 to 5 to fill a cell, Backspace to clear it and N to switch notes on or off.
The pad only offers the numbers that can exist on the board, and it greys out the numbers that are too big for the selected region or already used in it. When you place a number, the other cells with the same number turn orange, so you can check the no-touch rule at a glance.
A few tools help when you are stuck:
- Notes turns taps into small pencil marks, so you can keep track of the numbers still possible in a cell. A number you place is cleared from the notes around it.
- Hint fills in the cell with the fewest options left.
- Undo steps back one move, and Erase clears the selected cell.
- A number that breaks a rule with what is already on the board is refused, and the cells it clashes with flash red. A number that fits the rules but is still wrong shakes and counts as a mistake.
Pick Easy (5×5), Medium (6×6) or Hard (8×8) on the start card, or the Daily puzzle. Every board is checked by a solver before you see it, so there is always exactly one answer that you can reach by logic.
A simple way to solve a suguru
- Write 1 in every region of a single cell.
- Cross that 1 off the eight cells around it. Then look at the small regions nearby. A two-cell region next to a 1 often has only one spot left for its own 1.
- Look for regions with one empty cell. The missing number is the one not yet used.
- Go number by number through a big region. Ask where its 5 can go, then its 4, and so on. If only one cell is left for a number, place it.
- When a number has two or three possible cells in a region, find any outside cell that touches all of them. That cell cannot hold the number.
- Keep notes in the cells with two options. Once a neighbour is filled, they usually collapse to one.
Easy, medium and hard
The level changes both the size of the grid and the kind of thinking you need. Easy boards are 5×5 with plenty of given numbers, and you can finish them by placing the only possible number in a cell or the only possible cell for a number. Medium boards are 6×6 with fewer givens and need the touching trick from step 5. Hard boards are 8×8 with very few givens, and some steps may ask you to follow a short “what if” in your head: if this cell were a 2, its neighbour would have no number left, so it must be the other option.
Suguru and similar puzzles
If you like the region rules, Fillomino asks you to draw the regions yourself from the numbers inside them. Jigsaw sudoku keeps the irregular shapes but uses rows and columns of nine. Kakuro and killer sudoku bring in sums, and Star Battle has the same no-touch rule, only with stars instead of numbers.
How to play Suguru
- The grid is split into regions outlined by thick borders. Each region has between one and five cells.
- A region with two cells holds 1 and 2, a region with three cells holds 1, 2 and 3, and so on. Each number appears once per region.
- Two cells with the same number may never touch, not side by side and not diagonally.
- Some numbers are given at the start and cannot be changed.
- Every puzzle has exactly one solution. A number that does not match it is refused. If it clashes with a number already on the board, the clashing cells flash red; otherwise it counts as a mistake.
Suguru tips
Fill the single cells first
A region of one cell can only hold 1, so write it in straight away. That 1 then rules out 1 in all eight cells around it, which often settles where the 1 goes in the regions next door.
Use the shadow of a big region
A five-cell region must hold a 5 somewhere. If every cell still open for its 5 touches the same outside cell, that cell cannot be a 5. The same idea works for any number in any region: find the cells that touch all the remaining places and cross the number off there.
Look at pairs of two-cell regions
A two-cell region holds 1 and 2 in some order. When two of them lie end to end in a line, the middle cells touch, so the numbers must alternate: 1 2 1 2 or 2 1 2 1. One given number nearby, or a 1 already placed next to them, fixes all four cells at once.
Remember that every 2×2 block needs four different numbers
Any four cells in a square touch each other, so no number can repeat inside them. If three cells of a block already hold 1, 2 and 3, the fourth needs a 4 or a 5, so it must belong to a region of at least four cells.
Frequently asked questions
How do you solve a suguru?
Start with regions of one cell, which always hold 1, and with regions where only one number is missing. Then use the no-touch rule: every number you place removes that number from the eight cells around it. When a number has only one place left in its region, put it there. On harder boards, look for cells that touch every remaining spot for a number in a neighbouring region, because those cells cannot hold that number.
What is the difference between suguru and tectonic?
There is none. Suguru, Tectonic and Number Blocks are different names for the same puzzle with the same rules. Suguru is the original Japanese name, and Tectonic is the name you are more likely to see in Dutch and Belgian puzzle books.
Who invented suguru?
Suguru is credited to the Japanese puzzle designer Naoki Inaba, who has created a long list of pencil puzzles.
Can a number touch itself diagonally?
No. The same number may not sit in any of the eight cells around it, so diagonals count too. This is the rule that makes suguru different from most region puzzles.
Is there a daily suguru?
Yes. Pick Daily on the start card and everyone gets the same 6×6 board for the day. A new one appears at midnight UTC, and the other levels give you as many puzzles as you like.
Does my game save if I close the page?
Yes. Your numbers, notes, time and mistakes are kept in your browser, so the puzzle is waiting for you when you come back.
