The New Sudoku Players' Forum

[9X9]

This was pushed, gift wrapped, into the cave today and I like the cut of its jib.

Sudoku Genius by Tom Sheldon. "Welcome to Sudoku Hell ..."

Published in the UK (within the last couple of weeks) by Hodder & Stoughton as ... "the first ever book of genius level Sudoku ... nine progressively harder circles of Sudoku hell ... ending with a final puzzle that only the most hardened Sudokuist will crack"

Features:-

1. A nice introduction removing any remaining excuse we might otherwise proffer for not being able to spell "Suuji wa dokushin ni kagiru"!!

2. Logical methods explained up to and including forcing chains, the latter one being neatly entitled "Trail (sic) and Error".

3. Nine grades viz:-

Daunting
Tortuous
Merciless
Harrowing
Horrific
Maddening
Murderous
Devasting
Deadly

It's not a Pappocom book but it's a "must have"!!!

[Carcul]

Interestingly, this book was also published in Portugal about the same time. However, this book only confirms that hard puzzles cannot be found in published books.

ending with a final puzzle that only the most hardened Sudokuist will crack

The only comment to this sentence is a big laugh. Its incredible how some persons exagerate the hardeness of their sudoku puzzles just to sell a book. Regarding the last and (theoretically) toughest puzzle of this book, its one of the most simple that I have solved. But, however, I agree that it is a good book for beginers. But for all those out there that want really hard puzzles, please don't waste money in books (specially this one).

Carcul

[tarek]

I have a huge selection of puzzles generated by my solver at different levels.

With what i'm seeing at the moment, i'm thinking of publishing them
(As will all sudoku programmers).

On the other hand, I do think that the market is already more than saturated with sudoku books.

[lunababy_moonchild]

On the other hand, I do think that the market is already more than saturated with sudoku books.

Yes it is, but not with hard or very hard or very, very hard or extremely taxing puzzles for the experienced solvers amongst us.

Luna

[Carcul]

Hi Tarek.

I have a huge selection of puzzles generated by my solver at different levels.

Could you provide, if you don't mind, the two hardest puzzles that your solver can generate?

Thanks in advance.

Regards, Carcul

[tarek]

Yes it is, but not with hard or very hard or very, very hard or extremely taxing puzzles for the experienced solvers amongst us.

Interesting

Could you provide, if you don't mind, the two hardest puzzles that your solver can generate?

I haven't tweaked my solver to generate the extreme hard ones, my intention was to generate puzzles that the general public could solve & follow a solution that is clear & somehow easy to follow.

I can tweak it to produce harder ones, but at the moment the collection has puzzles (up to XY wings), definitely more difficult than the Times SUPERIOR ones. & increased difficulty is based on entertainement value (i.e How many non single elimination techniques are required).

So I'm not sure that my collection will satisfy your thirst Carcul ???!!!

I'll post 2 anyway when I get hold of my database

Tarek

[tarek]

I was trying to see if I can use my flashdisk here at work, the machine just erased the the whole thing. All the databases & solvers are basically wiped out (This is the first time this has happened).

I hope that I made some backups at home........if not, well.....

if that 's the case then apologies in advance for any delay in posting replys.

fingers crossed

[Carcul]

Hi Tarek.

So I'm not sure that my collection will satisfy your thirst Carcul ???!!!

I am not thirsty, I just like challenging puzzles and so I think the hardest puzzles generated by each solver may be good examples of them. It is also a good measure of the quality of the generator.

if that 's the case then apologies in advance for any delay in posting replys.

Don't worry, you have all the time in the world.

Regards, Carcul

[tarek]

Ahhhh.....

I managed to recover all data lost...........

Now.....

As I said, I only tweaked the genrator to produce puzzles requiring techniques up to a point that I chose.

I haven't selected maximum difficulty when generating puzzles (Systematic randomness if that makes any sense). All of MY PERSONAL generated collection stands at XY wings as a maximum (At the moment).

This is a non-symmetrical example showing variety if solved systematically:

Code: Select all

Puzzle #4527

 6 5 . | . 3 1 | . 8 2 
 . . . | . . . | 9 . . 
 4 . . | . 9 . | . 5 . 
-------+-------+------
 . . . | 3 . . | . 4 . 
 1 . . | . . . | . . . 
 . 6 . | . . 8 | . . 3 
-------+-------+------
 . 1 . | . 7 . | . . 5 
 . . 5 | . . . | . . . 
 2 8 . | 9 4 . | . 7 1 


Enjoy

[CathyW]

Good one tarek! Took me over 17 minutes using Simple Sudoku. I didn't actually use an xy wing (not sure if there was one in there?) but got to practice multiple colouring which helped with several eliminations.

[Carcul]

Hi Tarek.

Thanks for the puzzle.

I haven't selected maximum difficulty when generating puzzles

Perhaps you should.

Regards, Carcul

[tarek]

Good one tarek! Took me over 17 minutes using Simple Sudoku. I didn't actually use an xy wing (not sure if there was one in there?) but got to practice multiple colouring which helped with several eliminations.

Thanx Cathy,

I consider simple colouring more difficult than XY wing, I am sure that this puzzle can be solved using more advanced techniques, in a shorter period of time, Unfortunately the puzzle wasn't designed to be solved by more advanced techniques.

Now the puzzle above does not require colouring, Uniqueness, Forcing chains or anything more superior than XY wing.......

Try to solve it without colouring............

[tarek]

Perhaps you should.

I will do so, I'll keep you posted when I have generated enough to pick the hardes ones.

Tarek

[CathyW]

I consider simple colouring more difficult than XY wing, I am sure that this puzzle can be solved using more advanced techniques, in a shorter period of time.

Try to solve it without colouring............

Time reduced without colouring! Maybe you're right, but having finally got the hang of colouring I find it easier, at least on the simple level. I still make the occasional 'invalid move' on the multi-colouring. Simple Sudoku makes it much easier to spot XY wings by enabling you to highlight the 2 candidate cells. The real test would be to do this puzzle without a computer program and without having all the candidates filled in for you!

[tarek]

Took me over 17 minutes

I just noticed the number (17) now. WHAT !!! just 17 minutes

I am not sure if I know many people who use multicolouring in solving puzzles.

As a programmer, It would interesting to know how would 17 minutes score against other puzzles you solved.

At what level in solving do you start using ultracolouring (I mean the sequence of techniques used), & would that differ if you are not using the computer for pencilmarking

Are you planning to go to Lucca, because I've checked the UK sudoku championship grids & they were far inferior to the one I posted.

Tarek