How many unique sudokus are there?

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.

Does every Sudoku have a unique solution?

A properly formulated Sudoku puzzle has a unique solution. One can assume that a given puzzle actually is properly formulated, and use that in the reasoning, to exclude branches that would not lead to a unique solution.

How many 9x9 Sudoku grids are there?

They discovered that the number of possible 9 by 9 Sudoku grids is N=6670903752021072936960 which is approximately 6.671×10²¹.

Are there different types of Sudoku?

Sudoku types and classes

Sub Doku – Grids smaller than 9×9. Sometimes referred to as "Children's Sudoku" (especially the 4×4 variant) as the reduced number of possibilities makes them easier to solve. Super Doku – Grids larger than 9×9. Prime Doku – N×N grid where N is prime.

What is the minimum unique Sudoku?

An ordinary puzzle with a unique solution must have at least 17 clues, but this is not mathematically proven. There is a solvable puzzle with at most 21 clues for every solved grid, with the largest minimal puzzle found so far has 40 clues in the 81 cells. Similar results are known for variants and smaller grids.

Sudoku Tutorial #40 A must know technique.

What is rule of 2 Sudoku?

Rule 2 - Each column must contain the numbers from 1 to 9, without repetitions. The Sudoku rules for the columns on the grid are exactly the same as for the rows. The player must also fill these with the numbers from 1 to 9, making sure each digit occurs only once per column.

Can 1 Sudoku have multiple solutions?

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. There are examples of rank-3 Sudoku puzzles with 17 givens that are well-formed.

Which Sudoku is the hardest?

Expert Sudoku is a game for experienced Sudoku players with a very high level of difficulty. This hardest Sudoku puzzle is characterized by the fact that only a few numbers are shown in the Sudoku square, which consists of 9 small squares, where the cells are located 3x3.

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).

How many Sudoku are there in total?

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).

Is there a formula for 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.

Can you solve Sudoku mathematically?

In fact, mathematical thinking in the form of logical deduction is very useful in solving Sudokus. The most basic strategy to solve a Sudoku puzzle is to first write down, in each empty cell, all possible entries that will not contradict the One Rule with respect to the given cells.

Who invented Sudoku?

Sudoku Puzzle Creator Maki Kaji Dies At 69 Known as the "Godfather of Sudoku," Kaji created the puzzle to be easy for children and others who didn't want to think too hard.

Can I solve Sudoku without guessing?

Can all Sudoku puzzles be solved without guessing? According to Sudoku Of The Day, “Sudoku is a puzzle involving logic—no arithmetic or guessing is required!” While you can, guess, of course, if your guess is wrong, it will throw off the rest of the puzzle and you'll need to start over.

Can Sudoku help your brain?

Since solving Sudoku involves executive cognitive functions, most importantly problem-solving and decision-making, it can be a promising tool for neurorehabilitation and cognitive remediation therapy in neuropsychiatric disorders.

Is there 16 * 16 Sudoku?

16 x 16 sudoku puzzles work just the same as regular 9 x 9 sudoku puzzles, but they are, well, a lot bigger! Infact whereas a normal sudoku has 81 squares in it, a 16x16 sudoku has 256 squares in it, so you get a lot more puzzle for your money.

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 Sudoku 4 cell rule?

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. The clues are in the form of sets of four special clue-numbers.

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.

Is there 0 in Sudoku?

The cool thing about this enigma is that only two possible answers can fill each blank: zero and one—and each grid has a sole solution.

What is the smartest way to play Sudoku?

What is a hidden triple 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. It will be easier to understand this technique if you look at the example. Take a look at the highlighted cells.

What is the largest Sudoku puzzle?

The largest multi-sudoku puzzle consists of 280 sudoku grids and was achieved by Timeintermedia, Inc., Sugakubunka Co., Ltd., Wakara Co., Ltd. and Dwango Co., Ltd.

What are some fun facts about Sudoku?

The term Sudoku is certainly of Japanese origin, but the game is an American invention. Sudoku got to the forefront by Howard Garns in 1979, but it was named as Sudoku by Nikoli in Japan around five years later. It's no ordinary logic puzzle. The very first Sudoku Championship was held in 2006.