Play Hitori — Free

What is Hitori?

Hitori is a Japanese logic puzzle whose name means "alone" or "one person", and it plays a little like Sudoku turned inside out. Instead of writing numbers into empty cells, you start with a square grid that is already completely full of numbers and your job is to remove the extras by shading — blacking out — the right cells. When you are finished, every number that is still visible must be unique within its own row and column, none of the shaded cells may touch, and all the white cells must remain joined together as one continuous shape. It is a puzzle of subtraction rather than addition: the answer is hidden inside the grid from the very start, and solving it means carving away everything that does not belong.

What makes Hitori so satisfying is how three tiny rules interlock. On its own, "no repeated number in a line" would be easy — just shade one of every duplicate. But the moment you shade a cell you have to respect the other two rules as well: you cannot shade two neighbours in a row, and you must never wall off a group of white cells from the rest of the board. Those constraints push back against each other constantly, so a shade you would love to make is often forbidden, and a cell you assumed was safe turns out to be forced black. Every board on vygam is hand-crafted to have exactly one solution reachable by pure logic, so you never have to guess — there is always a next deduction waiting if you look closely enough. Puzzles come in three sizes: a quick 5×5 to learn the ropes, a meatier 6×6, and a genuinely challenging 7×7.

How to Play Hitori

Hitori has just three rules, and the grid is only solved when all of them are true everywhere at once. A shading is wrong whenever it breaks one of them:

• No repeated numbers. No value may appear more than once among the unshaded cells of any single row or any single column. Shading a cell hides its number, so if a number is duplicated in a line, shade the copies until only one is left showing.
• Shaded cells never touch. Two shaded cells may not be orthogonally adjacent — no black cell can sit directly above, below, left or right of another. They are allowed to meet only at a diagonal corner.
• White stays connected. All the unshaded cells must form one single group joined through shared edges. You may never shade a cell in a way that cuts one white cell, or a whole region of them, off from the rest.

Those three rules are everything. Notice how they pull against one another: the first rule tells you which cells you would like to shade, while the second and third rules constrain which of those you actually can. That tension is the whole game — when two rules disagree about a cell, the disagreement itself usually reveals the answer.

Hitori Tips & Strategy

Hitori rewards a small set of repeatable patterns. Once you can spot them at a glance, even the 7×7 Hard boards come apart one forced cell at a time. These techniques turn the three rules into a practical solving toolkit — and none of them ever require a guess.

1. Pairs and triples: the sandwich rule

   The most powerful pattern comes from combining the no-repeat and no-touch rules. When the same number appears three times in a row, side by side, you cannot shade two of them next to each other, so the only legal answer is to shade the two ends and leave the middle white — one copy survives and the black cells never touch. A closely related trick is the sandwich: if a value sits at both ends of a short run with the same value between them, such as 2 _ 2 where the outer twos would otherwise clash, the cell between a matching pair is often forced to stay white to keep everything connected. Scan every row and column for triples and tight repeats first; each one hands you guaranteed cells with no further reasoning needed.

2. Cornered cells must stay white

   Use the no-touch rule in reverse. Because two shaded cells can never be adjacent, whenever you shade a cell you instantly know that all four of its orthogonal neighbours must be white. Mark those neighbours as safe — circle them on vygam — and the board shrinks fast. This works hardest in the corners and along the edges: a corner cell has only two neighbours, so once one of them is shaded the corner itself is very often pinned white, and a white cell with a known value then forces the copies of that number elsewhere in its row and column to be shaded. Chaining "if this is black, that must be white, so its twin must be black" is the engine that drives most Hitori solutions.

3. Keep the white cells connected

   The connectivity rule is the one beginners forget, and it is often the deduction that cracks a tough board. Before you shade a cell, glance at whether doing so would trap a white cell or a small pocket of white cells with no way out. If shading a particular cell would isolate a neighbour — for instance, boxing a white cell into a dead-end where every other exit is already black — then that cell simply cannot be shaded, no matter how tempting the duplicate looks, and you shade its twin instead. Late in a puzzle, treat every remaining choice as a question of "does the white region survive?"

4. Work both directions at every cell

   Every cell lives in one row and one column, so treat it as the meeting point of two independent lines of reasoning. A number that looks safe from its row's point of view may be forced to shade because of a duplicate in its column, and vice versa. When you are stuck, pick the number that appears most often on the board and resolve its copies one line at a time — each duplicate you settle usually triggers a "safe" neighbour, which settles the next duplicate. On vygam you can tap Check at any moment to flash any broken rule in red, which is a fast way to catch a slip before it snowballs and to confirm a chain of deductions is clean.

Difficulty Levels & Puzzles

vygam ships Hitori in three tiers, and every board is authored to have a single guaranteed solution that logic alone can reach. Easy puzzles use a compact 5×5 grid with only a handful of shaded cells in the answer, so the sandwich rule and simple duplicate-spotting carry you smoothly from clue to clue. They are the ideal place to learn how shading, no-touch and connectivity feel together, and to build up speed reading pairs and triples at a glance before the connectivity rule ever becomes tricky.

Medium puzzles step up to a 6×6 grid with more duplicates to untangle, so you lean harder on chaining the "if black then neighbours white" deductions across intersecting rows and columns. Hard puzzles use the full 7×7 grid and the most shading of all, and on these the connectivity rule frequently becomes essential to place the final cells correctly. Your fastest completion is saved separately for each difficulty right in your browser, so you can chase a personal best on the 5×5 boards while you work your way up to the 7×7 set. Tap New puzzle any time to move to the next board in the current tier — the collection cycles, so there is always another grid waiting.

Hitori vs Sudoku & Other Logic Puzzles

If you enjoy Sudoku, Nonogram, Binairo or Futoshiki, Hitori will feel like a close cousin with a personality all its own. Like Sudoku it enforces a "no repeats in a line" constraint, but where Sudoku asks you to add the missing numbers, Hitori asks you to remove the surplus ones by shading — the numbers are already there, and solving means deciding which to erase from view. That shift from filling to shading gives Hitori a completely different rhythm: you are always weighing a shade against its ripple effects on the cells around it rather than searching for the one digit that fits.

Compared with a picture-forming puzzle like Nonogram, where you shade cells to reveal an image from numeric clues, Hitori uses shading too but for a logical goal rather than a visual one, and it layers in the no-touch and connectivity rules that Nonogram lacks. Against Binairo, which balances two symbols across a grid, and Futoshiki, which stacks greater-than signs onto a Latin square, Hitori stands out for its spatial rules — the way black and white cells constrain each other by position, not just by value. That blend of number logic and connected-region geometry is exactly why Hitori has spread through puzzle magazines and apps worldwide, and why it plays so well as a short, absorbing thinking break in your browser.

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