When was sudoku invented, and who invented it?
Some accounts attribute the game to a Swiss mathematician, Leonhard Euler in the late 1700s. The four lines that create the 9x9 blocks were added later. The
name Sudoku originates from Japan and is translated to mean solitary
number. A very similar puzzle called Number Place was published in
America in the late 1970's and in 1984 a Tokyo publisher saw the Number
Place puzzle and began producing a Sudoku magazine.
Can a puzzle have more than one correct solution?
No. Every Sudoku puzzle has one and only one correct solution.
Can I change or move the numbers that are already on the puzzle when I start it?
The prefilled boxes are sometimes referred to as "givens". No, you cannot change or move any of the givens in a Sudoku puzzle.
Do I need to be smart in math to be able to get the right answer?
No. After all,
you're not performing any operations on the numbers, like adding,
subtracting or multiplying. Sudoku is solved by using logic and
patience. It's basically a process of elimination.
Isn't sudoku really a trial and error puzzle?
No, it's not a
trial and error game, although some players say they use trial and
error. The best way to solve the puzzle is to eliminate all but one
possible number for each box – guessing can actually waste
time.
When I start a new puzzle, where should I begin?
You can solve a
Sudoku puzzle in any order or fashion you like. The natural human
tendency may be to start in the upperleft corner of the grid and work
down and to the right. This is rarely the best route to follow. Many
players like to look for the rows, columns, and blocks that contain the
most "givens". As a player becomes more experienced it usually gets
easier to spot a good starting place because the eye gets better
trained to see matching numbers in adjacent rows, columns and blocks.
What do I do if I make a mistake and end up with the same two numbers in a row, column or block?
You only have two choices – either start over or try to find and correct the
mistake. In most cases, players can back themselves into a corner where
most of the puzzle has been completed, but suddenly there is no correct
place to put a number to complete the row, column or block. This
problem is most likely the result of having two of the same numbers in
a row, column or block. This might be the only place where trial and
error might help, because in order to change the duplicate number
you'll need to change at least one other number to bring the puzzle
back in line with the rules.
Are there other variations of the game besides the standard 81 box grid?
Yes, there are
several variations. A few examples are: · Diagonal Sudoku 
adds the two main diagonals of the basic 9x9 box – so the
numbers along the diagonals must also run 1 through 9 and cannot
repeat. · High Five Sudoku  is a version available in some
Sunday newspapers that uses five 9x9 grids that overlap each other.
· EvenOdd Sudoku  uses boxes of two different colors
– one color box must contain only odd numbers and the other
color must contain only even numbers – all of the other
Sudoku rules apply.
How long does it take to complete a puzzle?
That depends on
the skill of the player and the difficulty of the puzzle. A basic
Sudoku grid with plenty of givens could be completed in just a few
minutes, whereas a more difficult basic puzzle or a more difficult
variation, like High Five Sudoku can take several hours. As you get
better at the game, your times will improve.
What kind of person would make a good sudoku player?
Just about anyone.
Players come from all walks of society. The game involves logic and the
process of elimination, so it takes some deductive reasoning and plenty
of patience. Beginners should not be discouraged if they're unable to
complete a puzzle – just keep trying!
Are Sudoku tournaments held?
Yes. You can find
information about Sudoku tournaments on the Internet. The first World
Championship Sudoku Tournament was held in Lucca, Italy in March of
2006. The winner was an accountant from the Czech Republic, 2nd and 3rd
place were one by US citizens  a Harvard University graduate student
and a software engineer from Google. The finalists had to compete by
solving 45 puzzles over two days. A number of Sudoku variations were
used in addition to the basic 81 block grid.
