What is a hidden pair in Sudoku?

"Hidden pairs" technique works the same way as "Hidden singles". The only thing that changes is the number of cells and Notes. If you can find two cells within a row, column, or 3x3 block where two Notes appear nowhere outside these cells, these two Notes must be placed in the two cells.

How do you find hidden pairs in Sudoku?

If you're looking for hidden pairs, you're looking for two numbers which only exist in two cells within that area – even though there will be other candidates in the same cell “hiding” them. For triples, you'll be looking for three cells, and so on.

What is an example of a hidden pair?

A hidden pair occurs when a pair of numbers appears in exactly two squares in a row, column, or block, but those two numbers aren't the only ones in their squares. In the above example, the 5 and 9 in red are a hidden pair.

What is the pair rule in Sudoku?

"Pointing pairs" applies when a Note is present twice in a block and this Note also belongs to the same row or column. This means that the Note must be the solution for one of the two cells in the block. So, you can eliminate this Note from any other cells in the row or column.

What are examples of hidden triples in Sudoku?

Hidden Triples

A Triple will consist of three pairs of numbers lying in three cells in the same row, column or box, such as [4,8,9], [4,8,9] and [4,8,9].

Hidden pairs - a Sudoku technique for beginners

What is the 45 rule in Sudoku?

The 45 rule is a basic solving-technique in Killer Sudoku. Each house (row, column, nonet) must add to 45 (the sum of the digits 1 through 9).

What is the rule of 3 in Sudoku?

If three candidates can be found in only the same three Cells of a region (Row, Column or Square), then one of these candidates is the solution for the first of these Cells, a second one is the solution for the second Cell and the last candidate is the solution for the third Cell.

What is not allowed in Sudoku?

You can use only numbers from 1 to 9. Each 3×3 block can only contain numbers from 1 to 9. Each vertical column can only contain numbers from 1 to 9. Each horizontal row can only contain numbers from 1 to 9.

Can there be 2 solutions to a Sudoku puzzle?

A well-formed Sudoku puzzle is one that has a unique solution. A Sudoku puzzle can have more than one solution, but in this case the kind of logical reasoning we described while discussing solving strategies may fall short.

Is Sudoku good for the brain?

Sudoku keeps your brain active and reduces the risk of Alzheimer's, a most common cause of dementia that affects a person's thinking and behavioural skills. Stimulates your mind: The game works on your logical thinking process as you are absorbed in solving a puzzle and eventually improve your number skills.

What is the hidden pairs technique?

"Hidden pairs" technique works the same way as "Hidden singles". The only thing that changes is the number of cells and Notes. If you can find two cells within a row, column, or 3x3 block where two Notes appear nowhere outside these cells, these two Notes must be placed in the two cells.

How can you tell a swordfish in Sudoku?

A Swordfish is a 3 by 3 nine-cell pattern where a candidate is found on three different rows (or three columns) and they line up in the opposite direction.

Can all Sudoku puzzles be solved without guessing?

The short answer is yes. Every proper Sudoku puzzle can be solved without ever having to make a guess. Another way of thinking about it is that every Sudoku puzzle can be solved logically. Even though it may require highly complicated solving techniques you're not familiar with.

Is there a formula to solve Sudoku?

For example, in the first and fourth columns beginning from the left of the 9×9 grid, we can form the following equations: m+n=a, g+n+f=g+c. In the second and last rows beginning from the top of the 9×9 grid, the following equations can be formed: b+g+f=a+g, e+n+m=a+b+d.

Why am I not good at Sudoku?

Whatever the reason, many Sudoku beginners are making a mistake, because they're not spending enough time looking at squares. Squares (there are 9 of them on the grid, and each contains 9 spaces) are a great place to look for opportunities to place numbers, because each square is made up of other rows and columns.

What does the red dot in Sudoku mean?

In the center-right square, there is a 6 (circled in red) which shows us that we can eliminate 6 as being in the top empty space of the column – so that space must contain 2 (marked in blue). Also, this means that the only remaining space in the green column must contain 6 (marked in blue).

What is the least clues in Sudoku?

Sudoku fanatics have long claimed that the smallest number of starting clues a puzzle can contain is 17. Now a year-long calculation proves there are no 16-clue puzzles. Sudoku is a number puzzle consisting of a 9 x 9 grid in which some cells contain clues in the form of digits from 1 to 9.

What is an evil Sudoku puzzle?

What is Sudoku Evil? Sudoku evil is a 9×9 grid sudoku puzzle with the highest possible level of difficulty. It's an advanced level only for experienced sudoku solvers.

What is the quadruple rule Sudoku?

Rules of Quadruple Sudoku

The object of the puzzle is to fill in the whole 9x9 grid with numbers 1 through 9 (one number per cell) so that each row, each column, and each of the nine 3x3 boxes contains all the nine different numbers 1 through 9.

What is the minimum time to solve Sudoku?

Normally it takes 4–6 minutes, but the really hard ones sometimes take 15 minutes to be solved.

Is 6 minutes good for Sudoku?

5 minutes is more than enough time to jump start your brain, re-evaluate your Sudoku strategy, and develop a new perspective on how to view the Sudoku grid. So “take 5” and give yourself a new chance at solving Sudoku puzzles!

What is a jellyfish in Sudoku?

A Jellyfish occurs when in four rows all possible cells for a given digit lie in four columns. This digit can be eliminated from the remaining cells of these columns. The technique also works when we replace rows with columns.

What should I look for first in Sudoku?

Look for the easy play first: When you first start to play a Sudoku puzzle, look for where you have the easiest opportunities to add a number. Usually this is where there is a crowded square or a row that is almost full of numbers.