♤ Solitaire♤ Spider中 Mahjong▦ Sudoku. About. New Game. Difficulty. EasyMediumHardVery hard. Help. ×. Very difficult Sudoku puzzles. Here are some seriously hard puzzles that are considered to be the most difficult to solve. If you come across a very difficult puzzle. Very difficult sudoku puzzles to print or play online. All the puzzles in this page are rated very difficult. Very Difficult Sudoku Puzzles very difficult. sudoku.


Author: Jailyn Herzog
Country: Tokelau
Language: English
Genre: Education
Published: 5 March 2016
Pages: 725
PDF File Size: 1.67 Mb
ePub File Size: 27.41 Mb
ISBN: 595-2-81732-773-1
Downloads: 27341
Price: Free
Uploader: Jailyn Herzog


Removing the 7 from the cell R5,C8 circled in red leaves us with two cells with the naked pair 1,8.

Very Difficult Sudoku Puzzles

Since no other cell in the same region can possibly have a 1 very difficult sudoku a 8, then cell R4,C7 which has the candidates 1,7,8 must be a 7. You have just broken the logjam. You will be able to solve the puzzle quickly now by looking for naked singles.

For very difficult sudoku difficult puzzles see my collection of printable free Sudoku puzzles. They come in five levels of difficulty. Sudoku XY-Wing Example 2 At the left is a variation of the XY-Wing pattern that occurs in my experience more often than the first example described above.


It is very difficult sudoku harder to spot. Sudoku Solver - Solving the hardest puzzles Our solver uses human logic to solve the daily puzzles, so our single step help function shows the next easiest square to fill!

Sudoku Solving Techniques

Origins of Sudoku Now you've played sudoku of the day online, aren't you intrigued as to how this highly addictive puzzle came about.

Like many people, I assumed that sudoku was Japanese, only to discover it was printed in a US magazine well before it reached Japan. More recently I read an article in a German newspaper that said that sudoku was invented by a Swiss very difficult sudoku, "Leonhard Euler" and is actually a subset of "Latin Squares".

This would mean those three numbers would have to be placed in either rows very difficult sudoku, 2 or 5.


We very difficult sudoku remove these three numbers as candidates very difficult sudoku any of the remaining cells in the column. Hidden subset This is similar to Naked subset, but it affects the cells holding the candidates. In this example, we see that the numbers 5, 6, 7 can only be placed in cells 5 or 6 in the first column marked in a red circleand that the number 5 can only be inserted in cell number 8.

Very difficult sudoku 6 and 7 must be placed in one of the cells with a red circle, it follows that the number 5 has to be placed in cell number 8, and thus we can remove any other candidates for this cell; in this case, 2 and 3.

X-Wing This method can work when you look at cells comprising a rectangle, such as the cells marked in red.

Extremely Difficult Sudoku Puzzles

In this example, let's say that the red and blue cells all have the number 5 as candidate numbers. Now, very difficult sudoku if the red cells are the only cells in column 2 and 8 in which you can put 5.

Very difficult sudoku this case you obviously need to put a 5 in two of the red cells, and you also know they cannot both be in the same row. Well, now, this means you can eliminate 5 as the candidate for all the blue cells.

This is because in the top row, either very difficult sudoku first or the second red cell must have a 5, and the same can be said about the lower row.

Expert Area - Extremely Hard Puzzles

Swordfish Swordfish is a more complicated version of X-Wing. In most cases, the technique might seem like much work for very little pay, but some puzzles can only be solved very difficult sudoku it.

So if you want to be a sudoku-solving master, read on!

Other interesting: