Quadruple Clue Sudoku

11 replies [Last post]
Joined: 11/30/2008

As the original inventor of "Quadruple Clue Sudoku" and the first designer of the same variant for the Second World Sudoku Championship 2007 at Praque, I am amused to discover one of your puzzles is given the so-called name "Quadruple". The two words "Clue Sudoku" were chopped off and it seems that the chopped-off words were compensated by minor changes outside the 9x9 grid with unclear and unexplained rules.

I suggest that, as a reputable organisation, your organisation should set a good example by giving due credit to the original inventors of the puzzles if their history of invention can still be traced at the moment. Failing which, their fate will end up like the Killer Sudoku, the identity of the inventor would be lost forever.

Furthermore, this would also reduce the number of such jokes as shown below:


Joined: 01/11/2010
Yap But if any way it's just

Yap But if any way it's just harnessing the Original Sudoku name then I am against it.

Joined: 09/25/2009
Well Quadruple is just the

Well Quadruple is just the combined name given and it's just a new version in the puzzle games arena which aims at providing better game strategies and game puzzles. But if any way it's just harnessing the Original Sudoku name then I am against it.

Joined: 11/30/2008
Quadruple Clue Sudoku in Sudokucup 2

I am glad to see my Quadruple Clue Sudoku appear again in Sudokucup 2 this year. Thanks for making my invented sudoku variant so popular by reproducing it under the name of "Quadruple". I hope my invented sudoku variant will appear in all major sudoku championships in the future.

Joined: 11/30/2008
Thanks to Marcel for his update

Thanks, Marcel for your update. You are one of the rare few that are so professional and ethical in the sudoku/puzzle world where plagiarism is so brazen, rampant and widespread.

Recently I read an interesting case in http://www.sudoku.com/forums.html where the victim lamented he was "still in shock and sick to his stomach". I understand his feelings because many of my sudoku variants have been plagiarized by others.

However, in view of the proverb "Imitation is the best flattery", I invite everybody to use my sudoku variants. I also spend my time surfing the Internet to detect admirers who use my sudoku concepts so that I can thank them for their "flattery".

Joined: 02/09/2009
Qualdruple Clue Sudoku


Sorry we did not mention you as the original inventor of Qualdruple Clue Sudoku. If we knew this when writing the blog entry about Quadruple Clue Sudoku at our puzzle weblog we had mentioned you directly. We made an update and mentioned your name after finding out we were wrong.

Please accept our apologies.


Joined: 11/30/2008
Reply to Katherine

Thanks, Katherine, for your admiration.

Henry Kwok (aman)

Joined: 12/06/2008
@Henry Kwok i admire every

@Henry Kwok
i admire every author who give us so many variants sudokus.as Karel Tesař said "For authors it is the best if people like their own types of sudoku puzzles".Karel Tesař is my friend,so are you.i just want to say that thank you all authors who make sudoku more interesting.that's why i often use a lot of time to write how i solved them step by step,for me,if i want to solve a sudoku,i only need solve it once,but to write a article,i should solve it twice or more to make sure every step is in logic.when you create a sudoku,you also will test it many times.i can understand all you authors' work,and thank you Karel Tesař bring us the sudokucup,i enjoy the puzzle,even if the match is over,i try to solve the puzzles left.Karel Tesař said someone didn't like this match at all,and so many times sorry for the mistakes,take it easy.i don't care the result,the feeling when solve them has already made me satisfied.that's the most important.

Minfang Lin/katherine/叶卡林娜,China

Joined: 11/30/2008
Reply to Stefan

Thanks, Stefan, for your clarification.

Henry Kwok (aman)

Joined: 11/15/2008
Variant of Quadruple Clue Sudoku

Dear Henry Kwok

In your first post you wrote: "...compensated by minor changes outside the 9x9 grid with unclear and unexplained rules."
I just wanted to point out that the puzzle in the contest is exactly your type of puzzle without any changes. The numbers outside of the grid are only there so that the participants could enter their solution in the answer sheet (only two rows or columns had to be entered). This is explained on the following web site:

This is only a small side aspect but it might reassure you that your idea was not taken and slightly altered in order to sell it as something new. I understand both your point as well as Kodyns point. He didn't know whom to acknowledge, he could perhaps have written "first appeared at WSC 2007, Prague".

Just the opinion of an ordinary participant of the contest...

Joined: 11/30/2008
Dear Karel Tesař, I choose to

Dear Karel Tesař,

I choose to agree and disagree. I agree with some of your words but disagree with others. I have to thank you for your agreeable words. Just think of it. I invented the 9x9 version of "Quadruple Clue Sudoku" in 2006, yet somebody came out with a "brand new" Sudoku variant with a 6x6 grid two years later in 2008 !

I would be working myself to death if I spend days and nights trying to protect my invention by creating infinite number of trivial versions with 3x3 grid, 4x4 grid, 5x5 grid, 7x7 grid, 8x8 grid, 9x9 grid, 10x10 grid, 11x11 grid, 12x12 grid, 13x13 grid, 14x14 grid, 15x15 grid, 16x16 grid, 17x17 grid, 18x18 grid, 19x19 grid, 20x20 grid, etc. I would also tire myself to death if I try to protect my invention by creating trivial versions with the two main diagonals, adding arrows or extra regions or making minor changes here or there in and outside the 9x9 grid.

Precisely because of this and because of the unfair practice of not mentioning the original inventor of a puzzle in the puzzle/sudoku world, I am more determined than ever to speak out, to clarify and to emphasize my points whenever I see somebody create or re-create or even re-invent my variants without giving me due credit for inventing my sudoku variants.

Without this type of push or drive, the whole puzzle/sudoku world will suffer. Without this type of acknowledgement, who is willing to be creative and innovative? Who is willing to be the "fool" to waste so much time and mental energy trying to create or invent something new? All "smart" people might as well relax, seek pleasures, "shake legs", sleep and wait to copy whatever the "fools" produce or bring along.

Henry Kwok (aman)

Admin's picture
Joined: 10/12/2008
Quadruple Clue Sudoku

I´ve been inspired by your sudoku variant. And I didn´t want to hide it anyway.
But what you're writing about the name of this puzzle and about the rules is not true from my point of view.
This is the copy of the rules in the booklet of WSC 2007:

Place a digit from 1 to 9 into each of the empty squares so that each
digit appears exactly once in each of the rows, columns and the nine outlined 3x3 regions.
Each set of 4 small digits in the intersection of two grid lines stands for the numbers in the four cells of the grid
adjacent to this set.


The Czech version before the translation was the same as the Czech version in the WSC 2007. I have created it with the book which I have
bought, your name was mentioned there but only in the list of authors. There was no connection to the Quadruple puzzle.
It' s true that the English translation is not the same. But as I can
see everyone has understood it well. So I don't think there is a problem with the meaning.
However it's your type of puzzle and nobody wants to dispute.

Really I don't know how to find an original author when I create
puzzles. It's because nobody writes about them. Nobody writes about the author of sudoku which is the base of your Quadruple (or as you better say Quadruple Clue Sudoku), Killer sudoku and any other variants. When the author creates the crossword, he also doesn't mention the author of the first crossword.
I'm an author of the Concentration Game sudoku (Pexeso) and I don't really think that somebody will write it's my sudoku variant in the future.
For authors it is the best if people like their own types of sudoku puzzles
and if the puzzles appear in a lot of tournaments. I think that you have achieved this point and you can be proud of it. Your Quadruple or Quadruple Clue Sudoku is such a type of puzzle that people like.

Karel Tesař (Kodyn)