How to Solve Suguru (Number Blocks Puzzle)

Suguru (also called Number Blocks or Tectonic) is a logic puzzle where you fill each outlined region with the numbers 1 up to its size, and no two identical numbers may touch — not even diagonally. This guide explains the rules in plain English, where to start, how the no-touch rule cracks the grid, and a free number game to warm up — no app or sign-up.

What Is Suguru?

The diagonal corner rule is the part that keeps tripping people up at first — it clicks into place once you see how it works alongside the region rule, and that is what this guide covers.

Suguru is a number-placement logic puzzle designed by Naoki Inaba in Japan. It also appears as Number Blocks (Puzzler, UK) and Tectonic (Netherlands) — same mechanics, different name on the cover. The grid is divided into irregular outlined regions of different sizes (typically one to five cells), and your job is to fill every cell using only logic. No guessing is ever required; every well-formed Suguru has exactly one solution.

Suguru shares the elimination spirit of Sudoku, but the constraints are different: no row or column rules, no sums. If you want cage-sum logic, Killer Sudoku covers how to play and solve that. Logic puzzles for adults maps where Suguru fits among other pencil puzzles.

The Rules of Suguru (in Plain English)

According to Puzzle Genius’s Suguru guide — a dedicated guide covering Suguru rules and strategy — the puzzle has two rules that must both be satisfied at the same time.

Rule 1 — Region fill. Every region must contain the digits from 1 up to the number of cells in that region, each digit exactly once. A one-cell region holds only 1; a three-cell region holds 1, 2, and 3; a five-cell region holds 1 through 5. No digit is repeated or skipped within a region.

Rule 2 — No-touch constraint. As sugurupuzzles.com states: “Boxes with the same number must never be neighbors — neither horizontally, vertically, nor diagonally.” Every cell has up to eight neighbors, and none may share its digit. The constraint crosses region boundaries: two cells in different regions that share even a corner cannot hold the same number.

💡 No-touch trick: the same digit can never sit next to itself, not even at a diagonal corner — it needs a gap of at least one cell in every direction before it can appear again.

Important: there is no row rule, no column rule, and no sum. In Sudoku a digit cannot repeat in a row; in Suguru two “3”s can sit in the same row on opposite ends of the grid with no problem — as long as they are not touching. This is the most common surprise for Sudoku players.

Where Do You Start? Small Regions First

The most reliable entry point is the smallest regions.

One-cell regions are free. They must hold 1 — fill them all immediately before doing anything else. Each placement starts generating no-touch eliminations right away.

Two-cell regions are nearly free. They must hold 1 and 2 in some order. Pencil-mark both cells with {1, 2} and move on — surrounding placements will resolve the order shortly.

Three-cell regions give you a range. Holds 1, 2, and 3 only — a narrow range that constrains a large patch of the surrounding grid before any digit is placed.

Four-cell and five-cell regions: narrow the field early, confirm late. Larger regions hold more digits (1 through 4 or 1 through 5), which means they start with a wide candidate range and rarely yield a forced cell at first glance. The useful move at this stage is not to stare at them longer but to note their extreme values: the highest digit (4 in a 4-cell region, 5 in a 5-cell region) cannot go near another cell already holding that digit, and because large regions sprawl across the grid they naturally touch many neighbors. Write in the maximum value wherever only one cell in the region is free from that no-touch conflict. Meanwhile, let the smaller regions around them resolve first — each placement in an adjacent 1-cell or 2-cell region bans a digit from one or two of the large region’s cells, steadily collapsing the candidate list. By mid-game, what looked like an open large region typically has two or three cells already forced by neighbor eliminations, and the rest fall quickly from region logic alone.

Find the tightest single cell. Scan for any cell whose candidates have already been reduced to one digit by no-touch eliminations. Write it in, then scan again — even one or two early forced cells will cascade into more.

Placing a digit bans it from all eight touching cells — including the four diagonal corners

The No-Touch Rule: Eliminate the Neighbors

The no-touch rule is the engine of Suguru.

What “no-touch” means in practice. Placing a digit bans it from all eight surrounding cells — the four orthogonal neighbors plus the four diagonal corners. A “2” in one cell blocks “2” from all diagonal neighbors simultaneously, which is where many solvers get tripped up early.

Why diagonals matter so much. Suguru regions are small and packed close. Two regions sharing only a corner still transfer the no-touch constraint through that single diagonal point, so one placement ripples eliminations into regions that barely graze it.

Working a small example. Place 1 in the top cell of a 3-cell region. That eliminates 1 from all eight neighbors across multiple surrounding regions. The bottom cell has a neighbor already containing 2, so it must hold 3. The middle cell resolves to 2. Three cells settled by two deductions.

Pencil-marking and the neighbor sweep. Write candidate digits in each cell, starting with the full range allowed by the region. Cross out any digit appearing in a touching neighbor. When a cell drops to one candidate, fill it in and sweep all eight neighbors again. This ripple-and-place cycle handles most beginner and intermediate puzzles without any guessing.

Combine Region Logic with Elimination (Cascading)

The no-touch rule and the region-fill rule feed each other in a cycle that locks down the grid section by section.

The solving cycle. Alternate between two sweeps:

Region sweep — check which digits are still unplaced and which cells can accept them. If any digit fits in only one cell, place it.
Neighbor sweep — after each placement, erase that digit from all eight neighbors’ candidates. If any neighbor is forced to one candidate, place it.
Return to step 1.

Most beginner and intermediate puzzles yield entirely to this cycle. One region resolves, its placements eliminate candidates in neighboring regions, and a cascade follows.

Region interaction. When two adjacent regions both need the same digit and their cells interlock, looking at both together surfaces deductions that neither reveals alone — useful in the mid-game when individual regions still have two or three ambiguous cells.

Connecting to Sudoku technique. The “naked single” (cell reduced to one candidate) and “hidden single” (digit that fits only one cell in a region) transfer directly from Sudoku. Our Sudoku guide covers both patterns; in Suguru the regions replace rows and boxes, but the elimination logic is identical.

Stuck? Recheck Small Regions and Corners

Feeling stuck almost always means a no-touch elimination or region deduction was missed. Before guessing — which a well-formed puzzle never requires — run through this checklist.

1. Recheck small regions. A two-cell {1, 2} region may now be resolvable: if one cell’s neighbors all contain 1, only 2 remains, and the partner resolves automatically.

2. Check every diagonal. The most common stuck-point is a missed diagonal. Trace all eight neighbors for recently placed digits — one overlooked corner often unblocks a whole section.

3. Look for “one away” regions. A region with one cell remaining is forced. Scan for nearly-full regions; they are easy to overlook when attention is on harder areas.

4. Try the hidden-single scan. Ask “Where can the digit 1 go in this region?” rather than “What can go in this cell?” This framing often surfaces a placement that cell-by-cell scanning missed.

5. Place any forced cell and restart. Each new placement generates a fresh wave of eliminations — sweep all eight neighbors again before concluding you are stuck.

Start with 5×5 or 6×6 grids until the no-touch habit is automatic. Free Suguru puzzles are available at sugurupuzzles.com with no account required.

10 Make 10 — free number puzzle Drop tiles so a row or column of touching numbers adds up to exactly 10. Free in your browser, no account needed. Try Make 10 ↓

For a grid-clearing challenge, Clear Sum has you keep or remove cells until every row and column hits its target sum. Free, no account. Brain games like Sudoku maps more options.

Frequently Asked Questions

How do you solve a Suguru puzzle?

Fill each region with 1 up to its size (no repeats). Apply the no-touch rule: no two identical digits may share an edge or corner, including diagonals. Start with one-cell regions (always 1), note small regions’ limited ranges, then alternate between region logic and neighbor-elimination sweeps. No guessing is needed.

What are the rules of Suguru (Number Blocks)?

Two rules: (1) each region contains the digits from 1 up to the number of cells in that region, each exactly once; (2) no two identical digits may touch — horizontally, vertically, or diagonally. The second rule applies across region boundaries: two cells in different regions that share a corner still cannot hold the same digit. There are no row rules, no column rules, and no sums involved.

Is Suguru like Sudoku?

Both use elimination logic, but the constraints differ. Sudoku restricts rows, columns, and 3×3 boxes; Suguru has no row or column rules — the same digit can appear multiple times in a row as long as no two copies touch. The diagonal no-touch rule has no Sudoku equivalent. If you like elimination-based puzzles, our Sudoku guide is a useful companion.

Are Suguru puzzles good for your brain?

They are a fun way to practice logical reasoning and sustained focus — the kind of deliberate, step-by-step thinking many people find genuinely satisfying. Suguru is a game, not a treatment, and it makes no guarantees about memory, IQ, or long-term brain health. If you find the challenge enjoyable, that is more than enough reason to keep going.

Sources: Puzzle Genius — Suguru From Scratch · SuguruPuzzles.com — Puzzle Solving Strategies

About the author: Jay M. spent years working in education — first at a private tutoring company, then running a coding academy branch — before moving into educational content creation. The guides and puzzles on Make10s come from a long-standing interest in how everyday number skills stay useful and enjoyable throughout adult life. Just for fun — not medical advice.