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sudoku GP 2020

I haven't viewed any publication from WPF concerning "what is sudoku report" (!!!!!). Normally, this report should have been the foundation for WPF sudoku competitions, more specifically sudoku GP here.

Can the WPF director give us a guarantee he will only select classic sudoku and sudoku variants for the 2020 competition?
As you have probably seen during the poll process on uk forum, sudoku hybrids examples, including examples taken from past sudoku GP, were clearly judged as not suitable for sudoku competitions.

If you want, we, sudoku players, can kindly admit the supremacy of WPC top players concerning tetrominoes placement puzzles, regional divisions puzzle, loop puzzles, etc... if you feel reassured then, we can play exclusively sudoku in sudoku GP and let these other categories of puzzles for puzzle GP, it will be better for everybody.


Hi Fred,

I'm still finishing the report, and (I think) that the WPF is waiting for that before deciding its next move. I am trying to do it as and when my time allows. However I am concerned that no-one at the WPF aside from myself is picking up the baton.

I am also doing an example review of the WPF's competitions in 2019. I hope that the WPF will appoint someone to carry on this work from this point forward, because it isn't right that this kind of thing rests on just one person's opinion, even if it is my own! As a sneak preview of this, I think that the 2019 GP series had a few hybrids and a few more things I would consider in a bit of a grey area.

Round 1 of 2020 looks to be more of the same, going by the IB.

Hi Tom,

Thanks for your answer. It's a pity you're alone to work on this subject.
I hope that when the report will be ready the WPF acts in adequation with the amount of work you made for this report.

In the meantime, I think the sudoku GP director should be careful about puzzle selection on this subject.


Can I request the sudoku GP director to give an answer on this subject? Thanks.

I would like to remind you the rules for sudoku GP (as written in the rules section):
"Each round will contain a mix of classic Sudoku puzzles and Sudoku variants."

There is no mention to hybrids in the rules, can we expect for once the rules will be followed?


Some hard words are written here, Fred. I strongly reject the accusations that I violate the competition rules. In the past three years and couple of months since I was elected, all the rules have always been followed. I don't take these charges as malicious, more as a yield of impatience.

Since the Sudoku GP serie was launched in 2013, the final selection of the puzzles received from the authors is at the discretion of the competition director. I am aware that the document „What is Sudoku report” is under construction. When any decision is made, I will adhere to all its parts.

I suppose that your remarks apply to Big Bands Sudoku and probably to some earlier puzzles. I know Big Bands is one of the oldest variants invented by Sinisa many years ago, I think even before the world championships began. Today we can call it hybrid, half-breed, mishmash or whatever, or simply variant.

I believe there are many more important things to decide about the future of WPF, but I urge the people who gave the order to get the report done, to expedite the final version and make a decision. As always, I am available for any questions, but this one is wrongly addressed.


It is pathetic to see how all people hide behind the "What is sudoku report" which is not yet published, thus we can't change anything. As if they didn't understand what were the issues in the past.

Please don't ask me to be patient, I've been patient in 2015, I've been patient in 2016, I've been patient in 2017, I've been patient in 2018, I've been patient in 2019 (and I could speak before 2015 too)... I think I don't need to prove again that I can be patient. I'll be patient for the "What is sudoku report", because I know it is done by a single person, which is a shame ! But what this person is doing, is trying to fix issues you and others created, without any kind of help from you and people who created the issue.

If you don't remember what the issue is, I'll recall it for you:
The WPF oversees sudoku competitions like wsc and sudoku gp. At a point in the history, It arrived more and more frequently to see inappropriate puzzles in these competitions (non-sudoku puzzles or puzzle hybrid containing sudoku part -i.e. sudoku hybrid). When I put the subject on the table, I got no answer... After 2 years of patience, I asked the WPF, and got the hypocritical answer that no rule existed which says world sudoku championship should be sudoku competition. After few months, without never saying what the issue is, they asked for a "what is sudoku report", which will be helpful to determine more precisely the limits, but don't be hypocritical yourself by pretending you don't know what a sudoku is at all.

The question is not concerning Big Bands at all, perhaps we need to wait the report for this one to know exactly. But the issue was not created by Big bands, you know it, I know it, we all know it. At a point people, including you, became crazy and allowed everything in sudoku competition. Even some authors have recoginzed some of their creations were not appropriate for sudoku competition.
The only people who still say that there were no issue at all are people in the WPF and you, sudoku GP director. This is not the good attitude to have.

So now, either you're able to give some kind of guarantee for sudoku GP 2020 (and again I'm not speaking about grey area, I'm speaking more about tetromino hybrid, if you really want an past example), either you're not, but in this case I fear it'll look like you're a part of the big mafia: these people who don't hesitate to chose puzzles which are going to be beneficial to their "WPC champions friends".

And I'm happy to have learnt a new bullshit argument: "If a puzzle existed before WSC began, then it is appropriate for sudoku competition", thank for this, lol !


This forum and all the discussions here only make sense if they take place in decent tones, with mutual respect for our views. And I will always be ready to answer any questions. But saying that someone is a crazy mafiozo who talks bullshit, I am sorry, at this level of conversation I do not want to participate.

Just to say thank you Nikola for your measured (and incredibly patient) responses.

Fred, you're not doing anyone any favours, least of all yourself or your cause. I'm happy that the Sudoku report is in progress and some things are improving *despite* your attitude. Thanks to Tom for pulling through there!

Just a few more words and I'll hopefully disappear for a while.

1. I always have to ask minimum 3 times before getting a kind of answer, which is kind of irritating (and first messages don't contain disrespect words).

2. Yes, my message is full of disrespect words, but if we look behind words, I just ask if the sudoku GP 2020 will be a sudoku competition and your answer is litterally "I'm the boss who decides and the rules say I can do what I want in the field of non-cultural puzzles." Followed by "no kind of issues never happened regarding rules".

I have to say honestly that I'm not sure I would win a disrespect battle against you, but ok...
So, yes, ok, do what you want, my opinion is made for sudoku GP 2020.
I'll come back in 2021 with basically the same question, but do not expect some kind of respect from me if your answer is still the same.


TiiT's picture

Fred has a point, despite the level of conversation.
I sincerely believe that sudoku is unrealisticly popular. But we don't see the potential of it, because we keep putting another puzzles in sudoku to make it more enjoyable to the minority.

Hi Tiit,

I've had a look at this in a bit of detail for 2019, and I think the GP has a more conservative balance of sudoku variations if you compare it to the WSC. I think one good example of this is the relative "protection" given to classic sudoku in the GP. 40% of the puzzles by volume (but only 25% by points) are guaranteed to be classics, which is a far higher figure than has been seen at recent WSCs. One real positive from the latest GP round (2) is that Sam took the opportunity to showcase really great quality classics.

That said, the GP is more-or-less following the WSC, and it is clear both are on a bit of a feedback loop where the original authors of the earlier more experimental online contests are running WSCs and shaping what these competitions look like based on how they have been before. If we are being honest with ourselves, we aren't solving sudoku competitions here, we are solving sudoku variations contests. Whilst the world sudoku champions are all supremely impressive, I don't know whether it's clear to say they are the best sudoku solvers full stop - for example, the finalists for the world record attempt in Prague in 2018 give an alternative view of who the best solvers might be.

Part of the problem is that "Puzzles" and "Sudoku" have this weird kind of segregation, so that more or less anything that looks like sudoku isn't seen as being welcome in "Puzzle" competitions and instead finds a home in "Sudoku" competitions. This leads to a category of innovative sudoku variations who don't really have a comfortable home in either world. I love solving these puzzles, and I'm sure you do, but 99% of sudoku solvers around the world don't have a clue.

Looking back, the main reason we have a Sudoku / Puzzle split is because there are different world championships for both. I don't think we really understand why this split exists anymore. I think there is definitely space to welcome back sudoku variations back into puzzle competitions, and I think there is also space to continue to have exclusive sudoku variations competitions. But one clear vision of this says that the main WPF sudoku competitions need to be a lot simpler and focus much more on classics if we want to be very clear about having stand alone sudoku competitions. In this scenario there is a currently a very big gap.

Still, that's just one point of view, and there are also reasons to carry on with the status quo, as Nikola argues for well - to one extent or another it's what the current community is (mostly) happy with. I'd be interested to hear what your vision on this looks like. I don't think we can rely on the WPF to be the driving force in these discussions - there's zero evidence of them being remotely proactive, and perhaps the best we can hope for from them is that they might get around to asking for volunteers for another committee they then give no support to.

TiiT's picture

Thanks for some interesting thoughts!
I don't think that sudoku champion should be determined only by solving classics. It would be same if crossword championship has only classic crosswords in it. Well there are lots of different and interesting ways invented how to make a crossword. I believe the only thing that is the same is that it has to be a crossword.

Same thing goes with sudoku. The important part is that you have to solve a sudoku and there can be different extra constraints, which are just giving you some restrictions - but the thing you need to do is to solve a sudoku.

Imagine if there was a paint it black crossword. First you need to paint some squares black and then solve a crossword in the remaining white cells. I'm pretty sure the first part has nothing to do with crosswords and therefore is not suitable in such competitions. It's also not suitable because it could be a deciding moment for the top players. You don't want deciding moment to be something else than crossword. The deciding moment needs to be a crossword, which decides who is going be a worthy champion, because it's a crossword championship.
You can draw a parallel with sudoku too and may possibly think out of many examples with that. Some of those examples have actually happened with some top players in WSC-s - including myself. And when I'm talking about myself, I have examples where I have gained advantages over other top players because of it and also examples where someone else has gained advantage over me because of it. I think it's not right when it happens.

I've been recently in a championship where all the puzzles were suitable for sudoku competition (in my opinion). This was this years ASC (Asian Sudoku Championship). There was some amount of classics (I woud say nearly 25% - 1 round out of 5 + 2 classics in each round), some amound of common variants and some interesting ideas how to combine the rules (round no. 5). I think the deciding moment was sudoku in there.
So, if you ask my honest opinion, then this years ASC is pretty much a perfect example how a world level sudoku competition should be like.

you should visit crosswords championship in Czech Republic. :-)
Because here it is done exactly how you described Paint it black crosswords.
You have crossword clues outside of grid listed by rows and columns, but actual crossword diagram is empty. So you don't know exact location and length for each answers. You have to figure out which words cross with other and in final solution, some cells in the grid may remain empty.
I would't say it is bad for crossword, because in fact, you have more possibilities how to combine words, so "crossing words" is skill which determine who is crossword champion.

That was just fun note, otherwise I get your point why you use that analogy for sudoku. But I love diversity of WSC, it shouldn't be only about puzzles where you need just observation and filling digits. Some thinking puzzles are needed too. So variants that are little puzzlish or nonstadard are fine, just authors must not get crazy with them and keep them approachable.

One point of view is also that, top players are forced to solve everything so they may feel damaged by some particular puzzles. Other "slow" players have choice to skip these puzzles and solve something else. If we put such questionable puzzles only into rounds, which offer alternative choice even for top players (more puzzles than is possible to solve for them within time limit), it could be better solutions than ban everything that is just slightly different.

I don't think your point of view is incompatible with the point of view saying that only classic sudoku and sudoku variants should appear in WPF sudoku competitions.
Of, course, saying "ban everything that is just slightly different." looks like a negative thing a priori.
But if we look at what the set of sudoku variants is (as described by the draft of 'what is a sudoku' report), I think it offers to us all things you spoke about: diversity, thinking puzzles, nonstandard variants, innovations, etc...
(I must confess I'm not sure I understand the word 'puzzlish', but as i see it, I don't think a classic sudoku or a sudoku variant could not be 'puzzlish'. I don't think 'puzzlish' is reserved to hybrids).

As I see it, hybrids, as described by first draft of 'what is a sudoku' report, describe the point where the nature of puzzle change and where placing digits is not the only purpose. Perhaps we can still discuss about where we set this limit (though I don't think it's exactly fair to start this discussion when the report is almost done, given that the report process offered last year full opportunity for these discussions). But I think the limit between variants and hybrids is a good limit to define which kind of puzzles are appropriate for sudoku competitions.


Who said anything about a ban? I don't think anyone wants to ban any puzzle, which sounds a bit ridiculous when you put it like that. It's more a question of which competitions they appear in.

That question requires you to think about two further questions:
1. Who is the WSC (as the most important competition) for?
2. What should the WSC look like?

I think after you are clear on those point that you can think about what the GP is for, whether it should be like the WSC or not, and whether there are sufficient outlets for sudoku variants or sudoku hybrids featuring sudoku.

To illustrate this point, whilst Tiit above says something like the ASC is perfect for a sudoku competition (and I'm sure many people would agree with him), perhaps (or perhaps not) you might say there weren't enough "thinking puzzles". Perhaps many others who struggle along with complex variations on the theme of sudoku might still look at the ASC and wonder exactly how some of those puzzles relate to what they solve in a newspaper.

I'm not trying to say there is a right answer here, just different points of view. Maybe if the WSC and GP become more restrictive, then you can have other outlets for the more outlandish sudoku variations. Vice versa if we maintain the status quo, or even relax the current restrictions the GP has, then maybe you have other competitions with a higher proportion of classics and standard variations. What exactly happens depends on the answers to the two questions above.

I have very little faith in the WPF getting around to answer these questions, so I am happy to continue these discussions and to hear different points of view expressed.

I have no right answer how WSC should look, because I do not try to find ideal WSC. ASC was mentioned as nice example of WSC-like competition - I agree. WSC with just classics and most known standard variants - could be nice WSC too.
I am for diverse WSC every year, I want to see it different every year.

I never said WSC must include a lot of thinking puzzles, sudoku related puzzles, jokers, liars, hybrids and so on - and if these are missed it's wrong. I just do not feel they are that bad to never see them again at WSC.
And I am talking about individual pieces, they could have their place at WSC now, competition was never based on them, but if authors make them in style that they can deform final results - then I agree it is bad (But that applies for any kind of puzzle)

That may be unique opinion, but that opinion exists :-)

Tom brought this point up here, but I'd like to rephrase it explicitly, because it's important to be aware of this during these discussions:

When we discuss the make-up of Sudoku competitions here / at the WPF / at the WSC, we have a strong pre-selection of points of view. And I'm not just talking about puzzlers like me whose opinion shouldn't hold much weight, everyone who's at the top at WSC is already someone who enjoys/excels at the current make-up of the competition. That's not to discount the opinions expressed here (at all!), but to encourage everyone to consider that there might be large audiences that we're excluding from the start.

It's a difficult problem to address -- I don't know for example if there are any competitive classic Sudoku scenes disjoint from the WPF that could be interviewed. But even running something like a survey among all Sudoku GP participants is likely to get a better slice of the Sudoku public than talking among the top 50.

It's a topic that I've run up against elsewhere: The German puzzle qualifiers are very much written by the core of the puzzle community for the core of the puzzle community, with little regard for potential other puzzlers. I believe this severely hinders growth of the community.

Clearly all of this depends on the goals -- Do we primarily want a WSC that focuses on improving the competition for current top solvers? Is it important for us to make Fred happy? Do we perhaps believe that Fred is representative of a larger but less loud demographic that we want to include? Do we want to tap into more of the solvers who primarily enjoy solving their classic Sudoku in a newspaper?

Quoting Tom:

I have very little faith in the WPF getting around to answer these questions, so I am happy to continue these discussions and to hear different points of view expressed

On that note, I'd like to stress that some input from the WPF board into these discussions would be much appreciated. E.g. with Jan we have an experienced Sudoku player from one of the countries with the largest player bases on the board -- perhaps you could weigh in?