How do I know if a Sudoku is Solvable?

Whether you've completed countless Sudokus in the past, or are trying out this kind of puzzle for the first time, it is important to remember that they are entirely solvable without having to rely on guesswork.

You simply need to know what to look out for ahead of time!

Remember that a unique solution is necessary.

Sudoku is a puzzle in which there is a unique solution, which means that there is only one possible way to fill out all of the cells correctly. Otherwise, you'd find that numbers appear more than once in a row, column, or 3x3 grid.

Analyze given numbers.

Keeping the information listed above in mind, you can ensure that you fill out the Sudoku grid as quickly as possible by analyzing the given numbers (the numbers that are locked in from the start). When a number is featured on a specific square, that means that it cannot appear again in that row, column, or 3x3 grid. This narrows down your options when it comes to filling the blank spaces in these areas, as you know which numbers you can count out beforehand.

Identify grid completeness.

Whether you're playing Sudoku online or on paper, some sections of the grid will be more 'complete' than others from the outset. It's often advised that you focus on filling in these sections first, whether you're aiming to complete a 3x3 box, line, or column. Doing so will make it easier to fill out the entire grid!

Used advanced methods.

If you are a more experienced player, you may want to try out more advanced tactics when filling out a Sudoku puzzle. For example, you could try speed-enhancing techniques such as looking for Naked Pairs, Triples, or an X-Wing Pattern.

If you're playing Sudoku online, there are plenty of steps that you can take should you run into any difficulties. For example, at Sudoku 247, you can tap the pencil icon to 'pencil' in potential numbers you aren't entirely sure about before locking them in later. This way, you will not encounter any time penalties by inputting the wrong number, but the grid looks as though it is properly filled in.

You should also be sure to take your time. While you may want to beat your previous score (or climb that leaderboard when playing online), rushing means that you are far more likely to make mistakes or grow frustrated. This also means that you are far more likely to say that the puzzle is unsolvable (when this is far from the case).

If you find that you are continuously struggling with Sudoku, consider switching to a lower difficulty level. For example, at Sudoku 247, you can choose between four difficulty levels: easy, medium, hard, and expert.

DISCLAIMER: The games on this website are using PLAY (fake) money. No payouts will be awarded, there are no "winnings", as all games represented by 247 Games LLC are free to play. Play strictly for fun.