What is the uniqueness trick in Sudoku?

As an application one has the Uniqueness Argument: Whenever one has a nonempty set of initially open cells, and two candidates at each of those cells, such that among these candidates each value occurs zero or two times in each row, column and block, then the actual solution differs in at least one cell from both ...

What is a hidden unique rectangle in Sudoku?

HIDDEN UNIQUE RECTANGLE (TYPE 2) : If two corners of the rectangle in the same Row/Column are "Bi-Value" Cells with the same candidates (forming a Naked Pair), if the candidates present in these "Bi-Value" Cells are also present in the two other corners of the rectangle among other candidates, and if one of these ...

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 hidden triple rule in Sudoku?

"Hidden triples" applies when three cells in a row, column, or 3x3 block contain the same three Notes. These three cells also contain other candidates, which may be removed from them.

What is Sudoku rule of 1?

Rule 1 - Each row must contain the numbers from 1 to 9, without repetitions. The player must focus on filling each row of the grid while ensuring there are no duplicated numbers. The placement order of the digits is irrelevant. Every puzzle, regardless of the difficulty level, begins with allocated numbers on the grid.

Uniqueness Sudoku Strategy BUG+1 Explained

What is the ambiguity rule in Sudoku?

During this process the designer must be careful not to remove two numbers that would cause an ambiguity (where those two numbers could be swapped and the puzzle could be completed two different ways, therefore having two solutions). This is what is called the sudoku ambiguity rule.

Are there unsolvable Sudoku puzzles?

Realistically, no! There are 6,670,903,752,021,072,936,960 possible solvable Sudoku grids that yield a unique result (that's 6 sextillion, 670 quintillion, 903 quadrillion, 752 trillion, 21 billion, 72 million, 936 thousand, 960 in case you were wondering). That's way more than the number of stars in the universe.

How do you know if Sudoku has unique solutions?

It turns out that for a Sudoku of rank n, at least n²-1 distinct symbols must be used for the puzzle to have a unique solution.

What happens when you solve Sudoku everyday?

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 best algorithm to solve Sudoku?

The simplex algorithm is able to solve proper Sudokus, indicating if the Sudoku is not valid (no solution). If there is more than one solution (non-proper Sudokus) the simplex algorithm will generally yield a solution with fractional amounts of more than one digit in some squares.

What are the weird rules for Sudoku puzzles?

And here are the special rules: “Any two cells separated by a knight's move or a king's move (in chess) cannot contain the same digit. Any two orthogonally adjacent cells cannot contain consecutive digits.”

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.

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 the 159 rule in Sudoku?

Normal sudoku rules apply: Each row, column, and region indicated by thick borders in the grid must contain the digits 1 to 9 once each. 159: Digits in column 1 indicate the column in which the digit 1 appears in that row (e.g. if r4c1 is a 6, r4c6 is a 1).

Should you ever guess in Sudoku?

Sudoku does not require guessing. In fact, when solving Sudoku puzzles, you're better off NOT guessing at all. Sudoku is a logic puzzle, using the power of simple deductive reasoning and process of elimination to fill in the gaps in the grid. Simply put – you don't need luck to play Sudoku.

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).

Is there math behind Sudoku?

To solve a Sudoku puzzle, one needs to use a combination of logic and trial-and-error. More math is involved behind the scenes: combinatorics used in counting valid Sudoku grids, group theory used to describe ideas of when two grids are equivalent, and computational complexity with regards to solving Sudokus.

Is there math in Sudoku?

Myth: You must be good at math to play Sudoku

But this is not true. Sudoku is not about adding or subtracting or doing arithmetic – it's about placing numbers 1-9 on a grid, without repeating any of the same numbers within the same row, column or square. Sudoku is not a “math” game, it's a logic game.

Is Sudoku high IQ?

From this case study it can be concluded that an individual who is skilled at solving Sudoku puzzles likely has a high general IQ. The results of the weak correlation between Sudoku scores and the WAIT test indicates that in some cases a high Sudoku doesn't necessarily mean a high general IQ.

How much time should it take to solve a Sudoku?

It is believed that the average Sudoku player spends approximately 20 minutes solving a typical Sudoku puzzle. For very hard puzzles, that number can be much higher. While the game itself can be challenging and complex, several strategies can be used successfully to find the solution.

What is diabolical Sudoku?

Classic sudoku: fit the numbers in the grid so that each row, column and square contains the numbers one to nine once only. If you think it sounds simple then try our diabolical sudoku to see how hard it can be. All Sudoku Diabolical Puzzles.

What is the smartest way to play Sudoku?

What is a hidden pair in Sudoku?

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.

Why not to play Sudoku?

Sudoku Can Increase Frustration Levels.

Even long-term Sudoku players can experience increased frustration when they level up to the next difficulty or encounter a puzzle that they just can't solve. The trick is to keep calm and take a break if you feel frustration rising.