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A little practice. A satisfying break.

How to play Suguru

Small regions, surprising connections. Learn to check both the bold borders and the neighbours just beyond them.

Play Suguru

Already playing in another tab? Switch back to that tab to keep your board and Undo history. These examples are separate from your puzzle.

Two rules, including the corners

  1. Each region contains 1 through its size, once each. A three-cell region contains 1, 2 and 3. A five-cell region contains 1–5. A single-cell region contains only 1.
  2. Equal numbers must never touch, even diagonally. Check the cells beside, above, below and at all four corners of your cell. The rule crosses region borders.

Unlike Sudoku, a whole row or column does not need every number. Distant cells in the same region still cannot repeat a number, even if they do not touch. Starting clues are fixed.

Before

A small teaching board with regions of three, four and five cells. Bold borders mark regions; this is not one of the playable board sizes.

The bottom-left 4 and the centre 5 touch at a corner, so they must differ. The two 1s at opposite ends of the top row are allowed: they are in different regions and do not touch.

Playable boards are 6 × 6, 8 × 8, 10 × 10 or 12 × 12, with Max 4, Max 5 or Max 6. “Max” is the largest region size, not the range of every cell. A three-cell region on a Max 6 board still permits only 1, 2 and 3.

Work through the next move

1. Complete the three-cell region

Action: Enter 2 in row 1, column 2.

After

The top-left region now contains 1, 2 and 3. None of the new 2’s neighbours is 2.

In the teaching board above, row 1 column 2 is the gap. Its three-cell region already has 1 and 3, so it needs 2. Its touching neighbours are row 1 columns 1 and 3 (1 and 3), and row 2 columns 1, 2 and 3 (3, 5 and 4). None is 2. The placement therefore satisfies both rules.

2. Reserve two numbers with a pair

A, B and C are a fragment of one five-cell region; its other cells contain 2 and 4. Complete candidates already account for every touching neighbour.

A and B belong to the same region, so they must differ even if their cells are far apart. Each allows only 1 or 3. Together they use 1 and 3, leaving 5 for C. The region’s other two cells already contain 2 and 4. No guess about the order of A and B was needed.

A cell outside the region that touches both A and B cannot contain 1 or 3 either: whichever order the pair takes, that cell touches both numbers. A cell touching only one of them does not get that conclusion.

Walkthrough: Region first, neighbours always

An original compact 3 × 4 teaching puzzle, not a playable board size. Bold borders show regions of three, four and five cells. Equal numbers must not touch, even diagonally.

Use fullscreen for a larger board, or follow the text lesson below.

Before

Original starting clues; question marks are the cells to solve.

Text transcript & checked moves

  1. Complete the small region. The top-left three-cell region has 1 and 3, so row 1 column 2 is 2. Its touching clues are 1, 3, 3 and 5; none is 2.
    Show board after move 1
    Place 2 at row 1, column 2.
  2. Check across the border. The right-hand four-cell region has 1, 2 and 3. Enter 4 at row 2 column 3. No filled neighbour is 4; the blank neighbour is still unknown.
    Show board after move 2
    Place 4 at row 2, column 3.
  3. Finish the five-cell region. The remaining region has 1, 3, 4 and 5, so row 3 column 2 is 2. Its neighbours are 3, 5, 4, 4 and 1, all different from 2.
    Show board after move 3
    Place 2 at row 3, column 2.

Each region now contains 1 through its size, and no equal numbers touch, including diagonally. Whole rows need not contain every number. Try a full-sized Suguru next.

Try your own Suguru

From small regions to shared neighbours

  1. Start with the cell’s range. Count its region’s cells, then rule out numbers already in that region or any touching cell. If one candidate survives, you have a cell single.
  2. Scan a region for a missing number. If only one cell can contain it, that is a region single. Check the diagonal neighbours too.
  3. Find shared neighbours. Suppose a region’s 4 can go only in A or B. A cell touching both cannot be 4, whichever place wins. Include every possible location before making this deduction.
  4. Use eligible 2 × 2 squares carefully. The four cells all touch one another. If all belong to regions of at most four cells, their distinct values must be 1–4. You cannot assume that on a square containing a cell from a five- or six-cell region.
  5. Look for naked pairs. Two cells in a region with the same complete two-number candidate set reserve those numbers. Remove them elsewhere in that region. Across regions, a pair requires the source cells to conflict (touch); a target must conflict with both sources before you remove either candidate.
  6. Look for hidden pairs. If two numbers have only the same two possible places in one region, remove other candidates from those two cells. Partial notes are not enough to prove this.

Common mistakes

The most easily missed conflict is diagonal. Another is entering 5 into a small region simply because the pad goes to 5 or 6. Do not apply Sudoku’s whole-row rule to Suguru, assume every 2 × 2 square contains 1–4, or remove a pair’s numbers from a cell that sees only one source. Recheck the region size and all eight neighbouring positions.

Learn the rules behind a hint

Start with singles. The later lessons explain more involved deductions when you need them. A candidate is a number that is still possible in a cell after checking the rules and earlier deductions. Your pencil marks may be incomplete: a missing note is never proof that a number is impossible.

Only one possible number

Start with 1 through the size of the cell’s own region. Rule out numbers already in that region or touching the cell, including diagonally, and any possibilities excluded by earlier checked steps. In a three-cell region, if 1 and 3 are ruled out, only 2 remains. A missing pencil mark is not an exclusion.

Only one place in a region

Every region needs each of its numbers once. If a four-cell region still needs 4 and only one cell can take it, that cell must be 4. Check all cells of the region, their complete possibilities and diagonal neighbours. The winning cell can have other possibilities.

Only one place in an eligible square

All four cells touch, including diagonally. The region-size condition makes 1–4 the complete range for this square.

The four cells of a 2 × 2 square all touch one another. When each belongs to a region of at most four cells, all four values are restricted to 1–4. They must differ, so the square contains every number from 1 to 4 once, even across region borders. In the example, only the bottom-right cell allows 4.

A square containing a cell from a five- or six-cell region does not meet this eligibility rule. The board’s overall maximum alone does not establish eligibility: inspect the four actual regions.

A region’s shared neighbours

Suppose a region’s 4 can go only in A or B. A target that conflicts with both A and B cannot be 4, whichever source takes it. A conflict means sharing a region or touching, including diagonally. Sources can be far apart within one region.

Include every possible source for 4 in the region. If C could also be 4, the target must conflict with C too. Seeing just one of two sources is not enough.

An eligible square’s shared neighbours

First establish the same eligibility as a square single: all four touching cells of the 2 × 2 square belong to regions of at most four cells, so the square must contain 1–4. If 3 can occur only in A or B within it, rule out 3 at a target conflicting with every possible source, here both A and B.

Conflicts can be through a shared region or touching, including diagonally. Include all possible locations for the digit inside the square; the source cells need not share a region. Do not apply this to an ineligible square.

Conflicting cells reserving numbers

Two cells that conflict and each allow only 1 or 3 must use both numbers. A target conflicting with both cannot use either. For example, diagonal neighbours A and B can form this pair even in different regions; a target touching only A does not qualify.

Conflicting cells reserving numbers (three or more)

Three or more mutually conflicting cells reserve an equal number of possibilities between them. For example, three cells allowing {1, 2}, {2, 3} and {1, 3} must use 1, 2 and 3. Every pair of sources must conflict, through a shared region or touching including diagonally. Remove these numbers only from a target conflicting with every source. Four sources require exactly four numbers, and likewise for larger sets.

The same works for larger sets when every pair of source cells conflicts and they collectively allow exactly as many numbers as there are cells. For three sources allowing {1, 2}, {2, 3} and {1, 3}, all three numbers are used. Remove them only from targets conflicting with every source.

Numbers reserving cells

If 1 and 3 in one region can occur only in A and B, those cells must contain those two numbers. Remove other possibilities, such as 2, from A and B. The same rule works for three or more numbers confined to an equal number of cells.

Numbers reserving cells (three or more)

Within one region, three or more numbers confined to an equal number of cells reserve those cells. For example, if 1, 3 and 4 can occur only in A, B and C, remove all other possibilities from A, B and C. Check every location of each reserved number in the entire region; each number needs a possible place. Four numbers require exactly four cells, and likewise for larger sets.

Check every cell of the region and every location of each reserved number. Different regions do not form a hidden subset merely because their notes look alike.

Checking each reserved number

A set of mutually conflicting cells is sometimes called a clique. If three such cells allow only 1, 2 and 3 between them, they reserve those numbers. Now inspect the sources for each digit separately.

For example, A allows {1, 2}, B {1, 2} and C {1, 2, 3}, and all three conflict pairwise. Only C can supply 3, so C must be 3. If instead a number has several possible sources, a target conflicting with all of those sources cannot contain it. The target need not conflict with source cells that cannot contain that particular number. Include shared-region and diagonal conflicts.

Different choices, the same destination

Suppose source A allows only 1 or 2. In another region, 1 can go only in B or T, and 2 only in C or T. A conflicts with B and C, but not T. If A is 1, B cannot be 1, leaving T as that region’s only place for 1. If A is 2, C cannot be 2, leaving T for 2.

Either choice makes T one of {1, 2}, so rule out T’s other possibilities. Check every possible value of A and every location of that value in the region: each case must leave the same single destination. Conflicts include same-region cells and diagonal neighbours. This is a complete case argument, not choosing a guess.

Notes, hints and controls

On a phone or with a mouse

Cell first is the default: select an empty cell, then tap or click a number on the pad. Turn Notes on to toggle small pencil marks instead of answers. Erase clears the selected cell. Fixed clues cannot be edited.

Number first lets you select a pad digit, then activate each target cell to enter it. With Notes on, each activation toggles that note in an empty cell. Selecting the digit does not write into the previously selected cell. Undo and Redo work one cell edit at a time. Focus, arrow navigation and scrolling never enter a number.

The pad shows up to the board’s maximum. In Cell first, selecting a cell in a smaller region blocks entry outside that region’s range; those pad digits remain available for inspection. In Number first, you can select a digit first, but activating a cell still checks its region’s range before writing. Boards fit the available screen width.

In Sudoku, turn Highlight same number on. In both games, touch-hold a pad digit to lock its highlight; hold it again to unlock, or hold another to switch. Unlock highlight is the visible alternative. A mouse or pen hold highlights only while held. Holds never write. A normal tap on a locked digit still enters it in Cell first or selects it in Number first, keeping the highlight lock.

With a keyboard

Tab to the board; arrow keys move between cells. With a board cell focused, digits enter directly in Cell first. In Number first, a short keyboard digit press selects that number, just like a short pad press; no hold is needed and the selected cell is unchanged. Enter or Space activates the focused cell with that number, or toggles its note with Notes on. N toggles Notes, and Delete, Backspace or 0 erases. Merely focusing a cell does not write. Activating an entry-mode button or a pad digit returns focus to the board after release. Tab leaves the board normally.

Ctrl+Z (Command+Z on Mac) undoes; Ctrl+Shift+Z (Command+Shift+Z) redoes. Ctrl+Y also redoes. These shortcuts work throughout the active play workspace, including hint and action buttons; text fields keep native editing. Holding a digit key does not repeat the edit.

With a board cell focused, Shift+digit locks or unlocks matching displayed numbers and notes. Space enters the locked number, or toggles that candidate in Notes mode, once per press. This also works in Number first: the inspection lock takes precedence for Space; Enter still uses the entry digit. Givens, region limits and assistance rules still apply. Use Unlock highlight to return to matching the selected cell.

Use notes as possibilities, not proof

Write every number that still fits a cell, then revisit the marks after each placement. Missing a pencil mark does not make a number impossible. Notes toggle only in empty cells; an answer can hide earlier notes. Undo restores the previous edit. Automatic note cleanup uses certified-correct placements, so an incorrect answer is not a sound reason to eliminate candidates.

Ask for a reason, then choose whether to apply it

One logical step offers a checked removal of pencil marks actually present, or a proved number with the reasoning needed to place it. Next number continues checked reasoning toward a placement. With no relevant notes to remove, a hint can still find a placement; you do not need to fill every cell with notes first.

The selected deduction’s action and short reason appear as bullets straight away. Use Previous and Next to follow earlier deductions one at a time. The markers follow the selected step; Return to final move restores the final explanation. Full checked evidence & cell links keeps every source, excluded number and Row / Column link available. Learn this rule opens the matching lesson in a new tab, leaving your original puzzle and Undo history in place. For a proved number, Apply enters the answer once, even with Notes on; Undo reverses that edit. For a note-removal hint, Apply note removals removes every listed mark as one undoable change. Candidate exclusions explain a proof and do not ask you to remove absent notes. An incorrect entry is rechecked first. Editing the board or canceling makes an old response unusable. Hints have bounded work limits: a stalled or exhausted result is not a claim that no logical move exists.

Relaxed play and the three-mistake challenge have different assistance rules. A paused or ended attempt protects the board from edits; follow the controls shown for that state. Undo restores entries and notes, but does not refund a challenge mistake or rewind its clock.

Size, maximum and difficulty are different

A larger board gives you more cells, while the maximum controls region size. Difficulty measures the checked solving work. Very easy and Easy focus on cell singles; Medium calls for region reasoning and shared neighbours. Current Hard boards need pair reasoning at separated stages. Very hard needs recurring combinations beyond pairs. A single difficult step does not set the whole board’s level.

For new boards, Max 4 is available in Very easy, Easy and Medium. Max 5 and Max 6 offer all five levels at each of the four sizes: 52 combinations in total. Older supported codes may describe earlier offerings or grading. Opening them keeps the original board, not a newly generated replacement.

Help → About this difficulty explains your board’s rating. Levels are provisional computational comparisons, not calibrated with players or interchangeable with other sites. The rating records a checked solving path; it does not say every person must use exactly that path.

Practical questions

Can I replay or share the exact same puzzle?

Yes. Share contains the puzzle code and link. Open a code to return to that identity; opening an existing supported code keeps its original board, even when new-puzzle offerings or difficulty grading have changed. A shared code or link contains the puzzle identity, not your entries or notes. Daily puzzles use the date’s published identity; keep the code if you want to return to that board later.

Are generated puzzles checked for a unique solution?

New puzzles must pass the supported family’s admission checks, including a unique solution and its logical rating requirements, before publication. Generation can fail within its work budget; the app reports that instead of publishing an unchecked board. A rating describes the checked solver’s work, not every human solving path or a promise that any in-progress hint request will finish.

Where is my progress saved?

Entries, notes and play state save locally in this browser after edits. There is no account or cloud backup. Your boards on the home page lists saved puzzles. Private browsing or clearing browser data can remove them. Undo/Redo history stays in the live play page and is not restored by a reload. Guides opened from play use another tab: return to the original play tab to keep that history.

What if saving fails or another tab has changed the save?

Keep the play tab open and follow its recovery message. A changed or unreadable saved copy is not silently overwritten. Use Share → Download this board to keep your current copy; recovery may also offer Download previous copy. Resolve the displayed conflict before relying on a later reload.

How do downloads and restoring work?

A downloaded JSON board includes progress; treat it as your backup rather than a spoiler-free share link. Choose Restore a downloaded board, then review and confirm the replacement. It replaces that board’s entries, notes and local time/challenge state, leaving other boards alone. Undo can restore entries and notes in the live tab, but does not restore time or refund mistakes.

Can I print a puzzle without my answers?

Choose Print board beside the play support controls. The reviewable preview starts with original clues only. Include current entries and Include notes are separate, optional choices; notes appear only in empty printed cells. The sheet includes the exact code and a canonical jacksbreak.com puzzle link, never a solution. Opening or closing the preview does not edit your board; a running timer continues normally.

Choose Print / Save as PDF, then A4 or Letter, portrait, 100% scale, with browser headers and footers off. On a phone, scroll the preview sheet to inspect it. Use Close preview (or Escape) to return to play; canceling the browser’s print dialog also leaves your puzzle unchanged.