What is Nikoli
Nikoli is a Japanese puzzle company,
and has published the books on Sudoku so many.
Nikoli is a puzzle company which makes not only Sudoku
but also creates original puzzles with the Japanese puzzle lovers.
Nikoli publishes many books and magazines,
but it is also a puzzle specialist company
which provides puzzles to the Japanese newspapers and publishing companies.
Nikoli's books or magazines can be obtained on bookstores only in Japan
but by the Internet, Nikoli's puzzle can be enjoyed
by accessing Puzzle Japan
And probably, you will find that there are a lot more puzzles besides Sudoku.
When you buy nikoli's books or magazines,
visit nikoli web site
and select "Purchase Books tag",
then you can order Nikoli's books and magagines.
Nikoli page of Wikipedia.
Sudoku in Japan
There are many books and magazines of related to Sudoku in Japan.
Therefore, a reader's level is very high and
a bad nature problem is disliked very much.
First of all, arrangement of digits must be beautiful.
Nikoli's Sudoku is certainly arranged point symmetry.
It cares not only about arrangement but about the row of a number,
or every question is loaded with various ideas.
Although the problem is made from the name of Sudoku all over the world,
how many will be accepted in Japan?
Too easy for PC
It is very easy to solve the problem of Sudoku using a computer.
It can be solved, if the introduction of programming is finished.
Upper level person can make a program to solve 1000 problems in 1 seconds,
using a cheap PC.
If it is solved so simply, there is no fun in this puzzle.
Sudoku is not made to be solved by computers,
it is meant to be solved by people
who finds the unexpected work or ideas that leads to pleasant feelings.
This is Sudoku, the puzzle.
Solve without an Eraser
There are various techniques for solving "Sudoku".
So many techniques exists from easy solving problems to advanced ones.
Part of the techniques are shown at
Key Solution (Puzzle Japan).
Techniques exists that are not shown on the site,
and it is challenging to find such keys.
Solving "Sudoku", a correct answer will be obtained
using the trial-and-error method and patience.
However, will you be interested in solving the puzzle in this way?
In Japan, upper leveled puzzle lovers use a ball-point pen
and solve Sudoku without correcting it at all.
In a commuter train, there are not few people
who solve the puzzle with a ball-point pen, instead of a pencil and an eraser.
History in Japan|
In 2005, a puzzle called “Sudoku” is in fashion in Britain,
and it is also affecting Australia and spreading all over the world.
Nikoli found the puzzle named “Number Place” in the United States,
but since the problem was boring, Nikoli revised it
which lead to people having a pleasant sensation
when the problem was solved, and was raised at a stretch,.
The puzzle was also named after Japanese Chinese character "Sudoku".
20 or more books of "Sudoku" which contains 100 questions
in one volume are already published.
Exposed cells should be less than 25.
The Professional Japanese puzzle creaters make sudoku problems
whose exposed cells are sometimes less than 20.
Most sudoku problems in Western World have too many exposed cells.
Problem on Thursday June 2 (medium)
of Guardian has only 20 exposed cells!
Why hand made?
"A well-made Sudoku is a pleasure to solve"
by Nobuhiko Kanamoto - Chief Editor of Nikoli
"Enjoyment is the most important thing"
by Hirofumi Hujiwara, famous Japanese Java programmer
by Maki Kaji, the Godfather of Sudoku, the President of Nikoli
a registered trademark of
NIKOLI Inc. in Japan.
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