Sudoku FlowFind the mistake #1
One digit on this board breaks the rules. The game is half finished: some digits were printed with the puzzle, the others were filled in by a player. Give yourself five seconds before the video shows it.
Reading the board
- 4Printed with the puzzle
- 4Filled in by a player
Where to start
This board has 58 digits and 32 of them are blue, so those 32 are the only suspects. The most crowded line is row 3, with 9 digits: a good place to start. How to find a mistake in Sudoku →
Try it here
Tap the digit you think is wrong.
Show the answer
It's the blue 4 in row 2, column 4. Column 4 already has a printed 4 (row 9, column 4). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 6.
Video transcript
On screen: One number is wrong. / How fast did you find it?
How fast did you find it? Tell us under the video.
Find the mistake #1
Exactly one blue digit repeats a digit that is already in its row, column or box. That digit is the mistake.
4 Printed with the puzzle 4 Filled in by a player
Answer: Find the mistake #1
It's the blue 4 in row 2, column 4. Column 4 already has a printed 4 (row 9, column 4). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 6.
Want more boards like this?
We also make a Sudoku app for iPhone, iPad, Mac and Android. There are no ads in it at all, it works offline, and when you ask for a hint it shows you the technique instead of just filling in a number.
Sudoku Flow is made by Rubigo Games, the developer of the Sudoku app recommended on this site.