Sudoku Notes - Why And How You Should Use Them

May 2023

Sudoku Notes in mobile web

Haven't used the notes feature yet?
Sit tight - this guide will make you at least 10X better sudoku player!

Using notes while playing Sudoku can significantly enhance your Sudoku performance! You will have shorter solving time and higher success with solving difficult sudoku boards that were previously unsolveable or very challenging to you.

Let's see how.

The Role of Notes in Sudoku

In Sudoku, note-taking means recording potential digit candidates in empty cells. That means that you, the player, will go over all of the empty cells in the board, or specific cells that you need more "help" with, and using the Notes feature, write the potential candidates of these cells.
These notes serve as visual aids, helping you keep track of possibilities and eliminate incorrect options. By taking notes effectively, you can significantly enhance your solving abilities.

PC view

Sudoku notes

Accelerating the Solving Process

One of the key benefits of using notes in Sudoku is improved focus and concentration. Seeing all the notes will help you maintain a clear overview of the puzzle, reducing distractions and preventing errors. By having a visual representation of potential candidates, you will make more informed decisions.
Furthermore, the notes enable you to analyze possibilities more systematically. Instead of mentally keeping track of potential numbers for each cell, they allow for a more organized approach. You can evaluate all candidates for each cell based on the information recorded, leading to faster, more accurate decision-making.
In addition, notes facilitate deductive reasoning. The process of elimination becomes easier with notes, as you can cross out eliminated options based on logical deductions. By systematically eliminating incorrect candidates, you can narrow down the possibilities and arrive at the correct solution more efficiently.

Mobile Phone view

Sudoku notes mobile phone

Taking notes in practice

Depends of what's works best for you, you can either start your game by going all over the blank squars and filling all candidates for each of them, or use it only in specific cases when you are running out of quick cells to fill. Either way, with each cell you fill, you should review all affected cells and update you notes accordingly.

Note taking example

We will start with the top left 3x3 box.
When checking cell B1, we recognize that both digits 4 and 6 fit there, and we don't have enough information yet to decide which one is the correct one, Let's take some more notes to help us take the final decision.

sudoku notes step 1

We continue to take notes for the entire 3x3 box, and we find some cells where exactly 1 digit is possible.
In our example these are digits 9 and 5 in cells A3 and C2 accordingly.
Since there are no other candidates in these cells, we can confidently fill them up and remove these digits from being candidates in other cells of the same 3x3 box.

sudoku notes step 2

Now we can see that we have 2 more cells with 1 candidate.
By filling cells B3, and C1, and removing these digits from being candidates in other cells,
we will remain with a single candidate in cell B1, the digit 6, and it will be the last digit to successfully complete this 3x3 box.

sudoku notes step 3

We filled cells C1 and B3, remaining only with cell B1 that has a single candidate, we will fill it as well.

sudoku notes step 4

Violla! We successfully used the Notes feature to fill the entire 3x3 box!

sudoku notes step 5

To take notes in Sudoku2 all you need to do is click the Notes button to turn Notes mode On and Off.
PC players can use kyeboard "N" key to toggle Notes mode On and Off.

A few extra notes:

Try it out!

Now you are ready to unleash the sudoku monster within you! don't go for the easy sudoku. Give a go at our Medium sudoku and test your new skills!
Play our Medium Sudoku now!

For more information about sudoku you can visit our tips and articles page