How to Play Suguru
Suguru (also known as Tectonic or Number Blocks) is a logic puzzle where you fill irregular regions with digits. Each region of size N holds 1 through N, and no two equal digits may touch. This guide teaches you everything you need to know.
What is Suguru?
Suguru is a logic puzzle played on a grid divided into irregular regions. Each region has a size (the number of cells it contains), and must be filled with the digits 1 through N, where N is the region size.
The key constraint is that no two cells containing the same digit may touch each other, including diagonally. This applies across all regions—not just within a region.
Your goal is to fill the grid such that:
Each region of size N contains the digits 1 through N exactly once
No two cells containing the same digit are adjacent to each other (horizontally, vertically, or diagonally)
The puzzle has exactly one solution
Unlike Sudoku, there are no row or column constraints. The region uniqueness rule and the no-touch rule are the only constraints you need.
Understanding Regions
Regions are the defining feature of Suguru. Each region is a contiguous group of cells outlined with a thick border. The number of cells in a region determines which digits it must contain.
Key Rules for Regions:
1.
Size determines range. A region of 5 cells must contain the digits 1, 2, 3, 4, and 5. A region of 3 cells must contain 1, 2, and 3.
2.
No repeats in region. Each digit appears exactly once in its region. A 4-cell region cannot contain two 2s.
3.
Adjacency rule is global. The no-touch rule applies everywhere, even between cells in different regions.
Example: A region of size 3:
Must contain exactly: 1, 2, and 3
If one cell already has a 2, the other two cells must hold 1 and 3 (in some order)
If a neighboring cell (in a different region) contains 3, then no cell in this region that touches it can be 3
Worked Example: 5Ă—5 Suguru
Let’s walk through a real deduction using a 5×5 Suguru puzzle. This example demonstrates how region elimination and adjacency constraints combine to force a cell.
Starting grid (5Ă—5, dots represent empty cells):
Region layout (letters A-F):
Region sizes: A=5, B=5, C=5, D=5, E=3, F=2
Target: Row 2, Column 4 (the empty cell in region B)
Let’s determine what digit must go in the empty cell at Row 2, Column 4.
Step 1: Region Elimination
Region B has size 5, so it must contain 1, 2, 3, 4, and 5. Looking at the given cells in region B:
Row 1, Column 3: contains 1
Row 1, Column 4: contains 2
Row 2, Column 3: contains 5
Region B already has 1, 2, and 5. The remaining candidates for our target cell are: 3, 4, 5
Wait—5 is already in the region, so we remove it. Candidates: 3 and 4
Step 2: Orthogonal Adjacency Check
Now check the cells directly adjacent (horizontally or vertically) to our target cell at Row 2, Column 4:
To the left (Row 2, Column 3): contains 5
To the right (Row 2, Column 5): empty
Above (Row 1, Column 4): contains 2
Below (Row 3, Column 4): empty
Our target cell cannot be 5 (already ruled out by region). It also cannot be 2 (the cell above contains 2). Candidates: 3 and 4
Step 3: Diagonal Adjacency Check (The Key Step)
Suguru’s no-touch rule includes diagonal neighbors. Check all four diagonal cells around Row 2, Column 4:
Upper-left (Row 1, Column 3): contains 1
Upper-right (Row 1, Column 5): empty
Lower-left (Row 3, Column 3): empty
Lower-right (Row 3, Column 5): contains 3
The lower-right diagonal neighbor (Row 3, Column 5) contains 3. By the no-touch rule, our target cell cannot be 3.
Conclusion: After eliminating 3, only 4 remains. The cell at Row 2, Column 4 must be 4.
The key lesson: region constraints narrow the candidates, then adjacency checks (including diagonals) eliminate the rest. The diagonal no-touch rule is what makes Suguru distinctive—always check all eight neighbors.
Essential Solving Techniques
Suguru puzzles require systematic elimination. Here are the core methods:
1. Region Analysis
Identify which digits are already present in each region. For a region of size N, the missing digits are your candidate pool. Start with small regions (size 2-3) where there are fewer possibilities.
2. Adjacency Elimination
For each empty cell, check all eight neighbors (orthogonal and diagonal). If a neighbor contains digit D, the empty cell cannot be D. This is the primary technique for narrowing candidates.
3. Forced Cells
When a cell has only one remaining candidate after region and adjacency elimination, it is forced—place that digit immediately. Each forced cell creates new adjacency constraints for its neighbors.
4. Region Uniqueness
If a region has only one empty cell remaining, that cell must hold the one missing digit. This is an instant solve for that cell, requiring no adjacency checks.
Tips for Success
•
Start with small regions
Regions of size 2 or 3 have fewer digit options, making them easier entry points. Complete these first to create adjacency constraints for larger regions.
•
Always check diagonals
The diagonal no-touch rule is easy to forget but crucial. Check all eight neighbors of every empty cell, not just the four orthogonal ones.
•
Use pencil marks (candidates)
Mark possible digits for each cell. As you place digits and eliminate based on adjacency, the remaining candidates become clear.
•
Look for forced chains
Sometimes placing one digit forces several others in sequence. Scan for cells that become forced after each placement.
Frequently Asked Questions
Can I guess in Suguru?
No guessing is needed. Every well-formed Suguru puzzle has exactly one solution reachable through logic using region uniqueness and the no-touch rule.
What does 'no two equal digits may touch' mean?
If a cell contains the digit 3, then no cell directly adjacent to it (horizontally, vertically, or diagonally) may also contain 3. This rule applies across all regions.
What's the best technique for beginners?
Start with small regions (size 2 or 3) where there are only a few digit placements to consider. Check each empty cell's neighbors to eliminate candidates based on the no-touch rule.
How is Suguru different from Sudoku?
Suguru uses irregular regions instead of a fixed 9×9 grid. There are no row/column constraints—only region uniqueness and the diagonal no-touch rule. This makes it a completely different solving experience.