Riverdoku · a logic puzzle of water and stoneFollow the numbers.Find the river.
Every number is how far the water has travelled from the spring. Dig the channels, lay the stones, and let the river run. Minesweeper meets a maze.
Free in your browser · no sign-up · one solution, no guessing
How to play Riverdoku
Three rules. Nothing else.
If you have played Sudoku, Minesweeper or Queens, you already know the feeling. Every deduction is one you can make and check. Nothing is left to luck.
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Every square is stone or water.
The pool in the ring of stones is the spring, where the water starts. Every other square is either river or river bed. Dig the channels, and the stones are what is left.
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The numbers count steps from the spring.
All the water reaches the spring, and neighbouring water differs by exactly one. A 9 means nine steps downstream. No more, no fewer.
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Water never flows in a circle.
There is only ever one way from the spring to any square. That is why every number means exactly one thing, and why every river has one answer.
Play Riverdoku online
A fresh river, right here.
Six by six for a quick one, seven by seven when you want to wander. Every board has exactly one answer and can be finished by deduction alone.
Tap a cell to dig the channel.
Tap to dig water · press and hold or right-click to lay a stone · drag to paint.
On a keyboard: arrows to move, Enter to dig, S to lay a stone.
The app
Take the river with you.
Quick play is only the shallows. The app has hundreds of hand-checked rivers, a new one every day, and a room for playing with friends.
- Six rivers
- Two hundred and twenty levels, from a 6×6 up to an 11×11, each with one answer.
- A new river every day
- Today's 7×7, a streak to keep, and a calendar for the days you missed.
- Play with friends
- Up to ten people dig the same river at once. First to finish takes ten points.
- Seasons and skins
- Earn a board for every month of the year, and a few from the films.
Questions
About Riverdoku.
A new logic puzzle, for people who love Sudoku, Minesweeper and a good deduction.
What is Riverdoku?
Riverdoku is a logic puzzle of water and stone. Every number on the board is how far the water has travelled from the spring. You dig the channels, and the stones are what is left. It plays like a cross between Minesweeper and a maze.
Is Riverdoku a kind of Sudoku?
Not quite, though Sudoku players feel at home. Like Sudoku, every Riverdoku has exactly one solution, and you reach it by logic alone, never by guessing. But instead of placing the digits one to nine in rows and boxes, you trace a river whose numbers count the steps from its spring. If you enjoy Sudoku, Minesweeper, Nonograms or Queens, Riverdoku is a new logic puzzle to add to the list.
How do you play Riverdoku?
Tap a square to dig water, and press and hold, or right-click, to lay a stone. Every open square must connect to the spring, neighbouring water differs by exactly one, and water never flows in a circle. Settle every square and the river runs.
Does every Riverdoku puzzle have one solution?
Yes. Every board is checked by a solver for exactly one answer, and for being finishable by deduction alone. There is always a next step you can work out.
Is Riverdoku free to play?
Yes. Quick play on this website is free, with no sign-up and nothing to install. The Riverdoku app is also free to download, and is supported by ads.
How hard is Riverdoku?
A 6×6 river takes a few minutes and is a gentle way to learn the rules. A 7×7 gives the river more room to wander. In the app the rivers grow to 11×11, with a new daily puzzle every day.