Grid Zen — Sudoku Online, No Guessing
- Plays on
- Desktop · Phone · Tablet
- Price
- Free · no download · no sign-up
Grid Zen is sudoku made calm and tactile: 81 soft white tiles on a mint board, digits that settle into their tiles with a little dip, and a row, column or box that hops in a wave the moment you finish it. Every puzzle has exactly one answer and can be solved by logic alone.
The rules never change: fill the empty tiles so that every row, every column and every 3×3 box holds each digit from 1 to 9 exactly once. Tap a tile to select it — its row, column and box light up, along with every tile holding the same digit — then tap a digit on the pad.
Levels is an endless ladder of puzzles, and level 20 is the same puzzle for everyone. The first ones leave more than forty digits and can be finished with the two simplest ideas: a tile with only one possible digit, and a digit with only one possible place. Further up the clues thin out toward twenty-seven and the puzzles ask for pointing pairs and naked pairs. Before a puzzle reaches you, a solver that uses only these human techniques must be able to finish it, so you never need to guess.
You have three hearts. A wrong digit costs one, flashes red and leaves; lose all three and the level starts over. Finish with no mistakes and no hint for three stars.
Notes are there for the harder puzzles: switch the pad to the pencil and jot small candidates into a tile. When you place a digit, it disappears from the notes of every tile it rules out. One free hint per level fills in a tile of your choice; the pad shows how many of each digit are still missing and hides a digit once all nine are placed.
The board, the tiles and the digits are drawn in 3D in the browser, so there is nothing to install. The game is sized for a phone held upright and works with a keyboard too.
How to play Grid Zen
Fill the grid so that every row, column and 3×3 box holds 1 to 9 exactly once:
- Tap an empty tile. Its row, column and box light up.
- Tap a digit on the pad. A right digit settles in; a wrong one costs a heart.
- Use the pencil to switch to notes and jot possible digits into a tile.
- Placing a digit removes it from the notes around it.
- A finished row, column or box hops in a wave.
- The bulb fills in a tile — one free per level.
- Three wrong digits and the level starts over. No mistakes and no hint means three stars.
Game modes
| Mode | What changes | Who it's for |
|---|---|---|
| Levels | An endless ladder of unique-answer puzzles: 43–44 clues at the start, 38 by level 4, 33 by level 9, 30 by level 16 and down to 27 from level 31. Up to level 15 singles are enough; beyond that, pointing and naked pairs. Three hearts per level, one free hint, three stars for a clean solve. | Everyone from first-timers to daily sudoku players. |
Tips for Grid Zen
- Start with the digit that already appears most often — the pad shows how many of each are left.
- Scan one box at a time and ask where a missing digit can still go; often only one tile is left.
- When a tile has only one candidate left in your notes, it is that digit.
- If a digit's candidates inside a box all sit in one row, it cannot go anywhere else in that row.
- Two tiles in a unit with the same two candidates own those two digits — cross them out of the rest of the unit.
Who made Grid Zen?
Grid Zen was built by crokocat game studio in 2026 — classic sudoku on 3D tiles drawn in the browser, puzzles generated with a single answer and checked by a human-technique solver so they never need a guess, notes, hints, hearts and an endless ladder.
About this game
- Controls
- Tap a tile, then a digit on the pad below the board. The pencil switches the pad to notes; the eraser clears a tile's notes; the bulb fills in a tile. On a keyboard: arrow keys move, 1–9 enter a digit, N toggles notes, Backspace clears notes.
- Supported devices
- desktop, phone, tablet
- Developer
- crokocat
- Genre
- Puzzle
- Release date
- September 2026
- Latest update
- September 2026
Related categories
Frequently asked questions
Is Grid Zen free to play?
Yes. Grid Zen is free on crokocat with no download and no sign-up — it runs in your browser on desktop, phone and tablet.
Does every puzzle have one solution?
Yes. Each puzzle is generated from a full grid and checked to have exactly one answer.
Will I ever have to guess?
No. Before a puzzle is used, a solver that only uses human techniques — singles, and on harder levels pointing and naked pairs — must be able to finish it.
What happens when I make a mistake?
A wrong digit flashes red, leaves the tile and costs one of three hearts. Lose all three and the level starts over.
How do notes work?
Tap the pencil to switch the pad to notes, then tap digits to jot them into the selected tile. Placing a digit removes it from the notes of every tile in the same row, column and box.
How many levels are there?
The ladder is endless. Puzzles start with 43–44 clues and thin down to 27, and level n is the same puzzle for every player.
Guides & tips
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