Play Suguru Online

What Is Suguru?

Suguru (also known as Tectonic, Tectonics, or Number Blocks) is a logic-based number-placement puzzle. The grid is divided into irregular groups (sometimes called cages or blocks) of varying sizes. Each group of N cells must contain the numbers 1 to N, and the core rule is simple: no two identical numbers may appear in adjacent cells — horizontally, vertically, or diagonally. That single constraint, applied across the entire grid, creates deep logical chains that make Suguru endlessly satisfying to solve.

The name “Suguru” comes from the Japanese word for “number groups.” It was created by Japanese puzzle designer Naoki Inaba, a prolific inventor known for originating dozens of pencil-puzzle genres. Suguru first appeared in puzzle magazines in Japan before spreading worldwide through newspapers, puzzle books, and online platforms. Today it sits alongside Sudoku, KenKen, and Kakuro as one of the most popular grid-based number puzzles.

Rules of Suguru

1. Fill each group with 1 to N. Every group of N cells must contain each digit from 1 to N exactly once. A group of 3 cells gets {1, 2, 3}; a group of 5 gets {1, 2, 3, 4, 5}.
2. No adjacent duplicates. Two cells that touch — horizontally, vertically, or diagonally — cannot contain the same number. This rule applies across the entire grid, not just within a single group.
3. Given clues. Some cells start pre-filled to ensure the puzzle has a unique solution. You cannot change these given digits.
4. No arithmetic. Unlike KenKen or Kakuro, Suguru involves no maths — only spatial logic and elimination.

How to Play Online

1. Choose your settings. Pick a grid size (6×6, 8×8, 10×10, or 12×12) and a difficulty level (Easy, Medium, or Hard).
2. Select a cell. Click or tap any empty cell to highlight it. Use arrow keys on desktop to move the selection.
3. Enter a digit. Click the on-screen number pad or press a number key to fill the selected cell.
4. Use Notes mode. Toggle 📝 Notes (or press N) to enter pencil marks instead of answers — useful for tracking which numbers are still possible.
5. Check your work. Press ✓ Check to highlight any incorrect cells in red for a few seconds.
6. Win! When every cell is correctly filled, the puzzle is complete and your time is recorded.

Suguru Strategy & Solving Tips

1. Start with Small Groups

A group of just 1 or 2 cells is trivially easy to fill. A 1-cell group always contains the number 1. A 2-cell group contains {1, 2}, and if one cell is given, the other is determined. These free digits immediately constrain neighbouring cells, giving you a foothold into the rest of the grid.

2. Eliminate Using Neighbours

At the heart of every Suguru solve is the no-adjacent-duplicates rule. When a cell contains a 3, none of its up-to-eight neighbours can also be a 3. Scan each empty cell and cross off any candidate that already appears in an adjacent cell. Often this alone reduces a cell to a single possibility — a naked single.

3. Use Group Constraints

Within each group, every number 1 to N must appear exactly once. If four of a five-cell group’s members are filled, the last cell is forced. Even when no cell is forced, combining group membership with neighbour elimination dramatically reduces candidates.

4. Look for Hidden Singles

A hidden single occurs when a digit can only go in one cell within a group. Even if that cell still has multiple candidates, the digit must go there because no other cell in the group can hold it. This technique is identical to the hidden single strategy in Sudoku and KenKen.

5. Chain Adjacent Groups

Because the no-adjacency rule crosses group boundaries, filling a cell in one group can trigger a cascade of eliminations in neighbouring groups. Work outward from clusters of solved cells and look for cascading singles — one placement forces another, which forces another.

6. Use Pencil Marks Liberally

Especially on larger grids (10×10 and above), pencil marks are essential. Write every possible candidate in each empty cell and update them as you make placements. Patterns like pairs and triples will emerge, narrowing possibilities faster than mental tracking alone.

Suguru vs Other Number Puzzles

Suguru vs Sudoku: Sudoku uses rows, columns, and 3×3 boxes on a fixed 9×9 grid. Suguru uses irregular groups of varying size and replaces the row/column rule with the diagonal-adjacency constraint. There are no “lines” to scan in Suguru — only local neighbourhood checks.

Suguru vs KenKen: KenKen combines Latin-square constraints with arithmetic cages. Suguru has no arithmetic at all — the constraint is purely spatial. This makes Suguru more accessible to younger solvers while still offering deep logical complexity.

Suguru vs Futoshiki: Futoshiki uses a Latin square with inequality signs. Suguru does away with rows and columns entirely, instead relying on irregular groups and adjacency. Both are excellent at building deductive reasoning skills.

Why Suguru Is Great for Brain Training

Suguru exercises spatial reasoning, pattern recognition, and logical deduction simultaneously. Because every cell has up to eight neighbours and belongs to a group of up to five, each placement cascades through multiple overlapping constraints — exercising working memory without requiring any maths. Teachers and cognitive therapists worldwide use Suguru puzzles for mental fitness, alongside crosswords and Sudoku.

Frequently Asked Questions

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