vendredi 18 octobre 2019

About future of sudoku competitions


If I ask some of my friends what are sudoku and masyu, I'll have 2 very distinct answers :
  • From a puzzle community friend, the answer will be « both are logical WPC-style puzzles »
  • From a friend not being in the puzzle community : He'll probably get a description of classic sudoku for sudoku and sure he won't know what a masyu is.
Sudoku is a universal puzzle, like rubik's cube or crossword, masyu is a well-known puzzle of the puzzle community.
That's why we have a world sudoku championship (WSC) and no world masyu championship.


This year, a report about sudoku was prepared in which 3 categories of sudoku are defined [it's not published yet, I hope the basics will not be changed]:

(A) Classic sudoku
(B) Sudoku variant
(C) Sudoku hybrid

I would add for purpose of discussion a 4th category :

(D) Non-sudoku puzzle.

Can we agree (D) puzzles are not appropriate in sudoku compeitions? No more of them in WSC, debate closed, thank you !

For the people outside puzzle community, I'll describe briefly what (A), (B) and (C) are.
(A) is basically what you think it is, sudoku as you regularly see in newspaper for example.
(B) is variation of it, it can be sudoku with added constraints (consecutive sudoku, etc..), or various geometry (irregular sudoku...), see this blog for lot of example.
(C) is for example a puzzle which mix sudoku and masyu rules. If you don't know what a masyu is, perhaps you'll have more problem to solve it than someone in the puzzle community.


The big question the world puzzle federation (WPF) has to answer now is : How a world sudoku championship should look like regarding these 4 categories of puzzles. The question was asked already after second WSC in 2007 by Simon Prett (not in these terms,but the question was really the same) and no answer was given by WPF. Answers were given by wsc organizers, by adding more of (A) in the championships (2008 – around 2011 I woul say). What we see now about classic sudoku (A) in recent WSC is a very small proportion (~6%) of the puzzles [proportion of points].

[Here technically, I don't count few classic sudoku that are inside variants rounds, because all top players know they'll not affect the ranking of competition. Only on rounds constituted exclusively of classic sudoku there is an impact from your level at solving classic sudoku].

Thus, I think modern WSC miss something. The postulate is not good. Postulate is probably that organizers want to please people taking part in the competition, and, as wpf is not acting outside puzzle community, there are a lot of people (too much) inside puzzle community who think classic sudoku are boring [we can see it for example in the press articles of this year WSC « Das Standard-Sudoku ist ja oft langweilig » said an organizer].
One of the not desired consequence of this is that a player « not very good at solving classic sudoku » can be world sudoku champion. This is not good ! A fair sudoku championship should contain enough classic sudoku to ensure the winner is good at solving both (A) and (B).
I think the wsc should also award best classic sudoku players, because (A) is what is most universal.
This year, there was 3 competitions for top players at WSC : world championship, world cup, and finals of Grand Prix. These 3 competitions based on very few (A) classic sudoku and big majority of (B) sudoku variants. Why this strange choice ??? Why not make the world cup to be a (A) classic sudoku competition ?
While it is important to have fair enough amount of classic sudoku at WSC, I see no problem if there is no classic sudoku at GP final, this is not the same competition. 2013 was a good example: only (B) sudoku variants. It could be a fair distinction between different competitions.


Sudoku being universal, I think world sudoku championship should be universal, too. During these first 14 years of WSC, the WPF was not able to see outside the puzzle community.
I think (C) is inappropriate in WSC, too. The reason is simple: sudoku hybrids are made for people knowing what masyu are, that is to say for the puzzle community. For people outside the puzzle community, these puzzles are not fair. If we want a universal championship, open to all sudoku fans inside and outside puzzle community, we must not allow puzzles from category (C) in sudoku tournament.

In conlusion, I would be happy if WPF take the only decision possible that would allow to make WSC a great competition for all sudoku fans, I mean :

  • WSC must contain fair amount of (A) classic sudoku, and awards should be given to the top players of (A).
  • WSC must contain only (A) and (B) and the top player of this competition is awarded as being World Sudoku Champion of the year.

By fair amount of (A), I mean it can be fair amount of rounds, fair amount of % of points, or anything else, i don't have real preference [but no, I don't consider 6% as being a fair amount].

I hope once in my life I will be able to consider the winner of a WPF competition as World Sudoku Champion...

vendredi 21 octobre 2016

Killer sudoku N°14


Voici le 500ème puzzle publié sur ce blog !
Ce sudoku est également le dernier qui sera publié ici. J'espère que vous, chers lecteurs, avez apprécié et continuerez à apprécier résoudre les sudokus que vous trouvez gratuitement ici. Si vous avez apprécié mon travail, prenez le temps d'écrire un petit commentaire à la fin de ce message, ça me fera le plus grand plaisir. Avez-vous un favori parmi les puzzles publiés ici? Faites-le nous savoir.
Frédéric Stalder


Here is the 500th puzzle published on this blog!
This sudoku is also the very last one to be published here. I hope that you, dear readers, have enjoyed and will continue to enjoy solving Sudokus that you find here for free. If you enjoyed my work, take the time to write a little comment at the end of this message, it will give me the greatest pleasure. Do you have a favorite among the puzzles published here? Please let us know.

Frédéric Stalder


Règles

  • Règles classiques du sudoku,
  • Le nombre en haut à gauche d'une zone correspond à la somme des chiffres de cette zone. Un même chiffre ne peut se répéter au sein d'une zone.
  • +++++++++++++++

  • Classical rules of sudoku,
  • The value on the top-left corner of a shaded area is equal to the sum of this area's digits. No digit can repeat within an area.

Sudoku classique N°88

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.

Odd sudoku N°5

Règles

  • Règles classiques du sudoku,
  • Chaque case grise doit contenir un chiffre impair.
  • +++++++++++++++

  • Classical rules of sudoku,
  • Each shaded cell must contain an odd digit.

Sudoku classique N°87

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.

Sudoku Diagonal N°13

Règles

  • Chaque ligne, colonne, région de 3x3 cases et diagonale principale contient les chiffres de 1 à 9.
  • +++++++++++++++
  • Every row, column, 3x3 region and main diagonal contains the digits 1 through 9.

lundi 17 octobre 2016

Sudoku classique N°86

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.


Grille créée pour le tournoi de Trébeurden
(25 septembre 2016)

Sudoku classique N°85

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.


Grille créée pour le tournoi de Trébeurden
(25 septembre 2016)

Sudoku classique N°84

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.


Grille créée pour le tournoi de Trébeurden
(25 septembre 2016)

Sudoku classique N°83

Règles

  • Remplir la grille avec des chiffres de 1 à 9, de telle manière que chaque chiffre apparaisse exactement une fois dans chaque ligne, colonne et région.
  • +++++++++++++++

  • Fill the grid with digits from 1 to 9, so that each digit occurs exactly once in every row, column and outlined box.


Grille créée pour le tournoi de Trébeurden
(25 septembre 2016)