# What is the rule of 3 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 the trick to solving Sudoku puzzles?

5 Best Tips for Playing Sudoku
• Look for the Easy Solutions. Many puzzles will leave one or two blanks either in a line or in a box. ...
• Seek the Missing Numbers. ...
• Keep Scanning the Entire Puzzle. ...
• Constantly Re-Evaluate the Grid. ...
• Be Patient and Enjoy the Hunt.

## What is the Sudoku Killer rule?

Each row, column, and nonet contains each number exactly once. The sum of all numbers in a cage must match the small number printed in its corner. No number appears more than once in a cage. (This is the standard rule for killer sudokus, and implies that no cage can include more than 9 cells.)

## What are triples and quads in Sudoku?

This technique is known as "Naked Subset" or "Disjoint Subset" in general, and works by looking for candidates that can be removed from other cells. Naked Pairs are when there are just two candidates being looked for, Naked Triple when there are three, and Naked Quads when there are four.

## How do you find hidden pairs and triples in Sudoku?

Looking for hidden groups

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.

## How to solve Sudoku puzzle 3 3?

The goal of sudoku is simple: fill in the numbers 1-9 exactly once in every row, column, and 3x3 region. For example, look at the above puzzle and compare it to the solved version below. Notice that every row, column and 3x3 region contain every number from 1-9 exactly once. The same puzzle, this time solved.

## What is an example of a hidden pair in Sudoku?

Hidden Pairs can be buried under lots of other candidates as shown in the right example: r1c12 is a Hidden Pair for candidates 4 and 7 (in this case they are hidden in row 1 and in block 1), but those cells house another 10 candidates, which can all be eliminated.

## 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 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.

## What is the average time to solve a Sudoku?

It can be incredibly challenging to solve a Sudoku puzzle. That's what makes it fun. 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.

## Is there only one correct answer in Sudoku?

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. The solver's jobs is to ﬁll in the remaining cells so that each row, column and 3×3 box in the grid contains all nine digits. There's another unwritten rule: the puzzle must have only one solution.

## What is the best order to solve Sudoku?

The easiest way starting a Sudoku puzzle is to scan rows and columns within each triple-box area, eliminating numbers or squares and finding situations where only a single number can fit into a single square. The scanning technique is fast and usually sufficient to solve easy puzzles all the way to the end.

## 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 red dot in Sudoku?

The central column (in green) has only two spaces left, and they must contain a 2 and a 6. 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).

## 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.

## How do you know if a Sudoku is unsolvable?

Solvable A sudoku puzzle is solvable if there is only one way to fill in a sudoku board to make it valid. Cell A cell is a position on the Sudoku board. Cells contain cell values and pencil-marks (denoted by (n, {a, b, ..., j}) with n the value of the cell and {a, b, ..., j} the set of pencil-marks).

## What is Sudoku 4 cell rule?

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 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 fish in Sudoku?

Nowadays, any single-digit pattern that compares 2 partially overlapping constraint sets of equal size is called a fish. In standard Sudoku, the sets can contain rows, columns, and boxes. In Sudoku Variations with additional constraints, any combination is possible.

## How do you sum 15 in Sudoku 3 by 3?

One way to determine what the magic sum should be is to add the sums of all three rows and then divide by the number of rows. Since 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45 and 45 ÷ 3 = 15, then 15 is indeed the magic sum.

## What is 3 * 3 box in Sudoku?

A 3x3 box is a group of nine cells three cells wide and three cells high as shown by the two large teal squares in Figure 1. The nine 3x3 boxes in a sudoku puzzle are delineated by the bold lines.

## What is the dead end in Sudoku?

There is no solution. Out in the Sudoku verse, the other name for it is the bivalue universal grave or graveyard. And basically what that means bivalue means two possibilities in each space. And then universal that it's every space on the board, and then graveyard means that it's basically a dead end.

## What is the fastest algorithm for Sudoku?

Backtracking algorithm is the fastest algorithm to solve sudoku puzzles, It is by far the fastest compared to the other two methods. Also, let's note that each algorithm was faster with harder problems than with easier problems.