So… many of you have asked for a book with only the most difficult of my Killer Sudokus. In “Revenge of Killer Sudoku 6” I dropped the easy puzzles and focused on THINKER and BRAIN levels of difficulty. Well, this time, I’m raising the bar at least two notches up. There are no more COOL and THINKERs! Instead, there are now just BRAIN, IQ and INSANE puzzles!

Yes, that’s right. INSANE. You asked for it. Here they are. Just to make things clear, what you get in this book is:

• 40 BRAIN (5 diagonal)
• 50 IQ!
• 10 ZERO (including 8 ZERO INSANE)
• 11 INSANE!

It doesn’t get any better than this. The summer will be HOT with these puzzles! Try them!

Well, I decided to change that and therefore I prepared and published a book with only really EASY Killer Sudoku puzzles. If you’ve been scared to try the Addoku or Sumdoku (as these puzzles are also known), this book should take away that fear. The instructions are clear and nicely introduce you to Killer Sudoku solving techniques.

Finally, this book is also suitable for children who can add and subtract. That’s all they need to know to solve these puzzles. So, it’s a nice gift for your kid to keep themselves busy over the coming summer.

So, what are you waiting for?
Try it, it’s worth it! The book is just $7.95 or £4.99!!!
(NOW DISCOUNTED TO $7.16!!!)

By the way, isn’t that the prettiest book cover I ever created?

Oh… for those of you who are already well versed at solving Killer Sudoku, I have some good news. I also published a different book only with the most difficult Killer Sudoku, yes, including some INSANE Killers! More about that in a few days… you can already find a link on the Killer Sudoku page.

Well… this time I present you a book of somewhat larger picross puzzles! Almost all puzzles in this book are between 30×30 and 40×40 in size.

And one more interesting fact about this book: almost all images were drawn by my Mom! And I think the grids turn into beautiful images. Thank you so much, Mama!

IMPORTANT: The book is currently discounted by 10% Amazon US! Not sure how long it will last, it is not under my control. So better get it now.

So far, there are 3 volumes of classic Calcudokus (I tend to make them more difficult than other authors, so be careful!), one with Calcudoku for Kids (easy stuff, but not trivial and very good for learning!) and one very special book with overlapping Calcudoku puzzles – Samurai CalcuDoku.

So… here we go…

Pirate Games

Five pirates have obtained 100 gold coins and have to divide up the loot. The pirates are all extremely intelligent, treacherous and selfish (especially the captain) each wanting to maximize the number of coins that he gets.


It is always the highest ranked pirate who proposes a distribution of the loot. All pirates vote on the proposal, and if half the crew or more go “Aye”, the loot is divided as proposed.

If the captain fails to obtain support of at least half his crew (which includes himself), all pirates turn against him and make him walk the plank. The pirates then start over again with the next most senior pirate as captain (the pirates have a strict order of seniority denoted by A, B, C, D and E).


Pirates’ preferences are ordered in the following way. First of all, each pirate wants to survive. Second, given survival, each pirate wants to maximize the number of gold coins he receives. Finally, each pirate would prefer to throw another overboard in the case of indifference.

What is the maximum number of coins that the original captain should propose for himself? And for others?

So we start the year with a gift for children. Quite appropriate I would say. It’s a Griddlers Nonograms Hanjie Picross game for Kindle, but this time, the puzzles are of suitable level to be solved by children. Starting clues (black and white cells) are given so that your kid would know where to begin.

It’s a nice change. Remember, I’ve already released two games for kids on Kindle, Sudoku for Kids for Kindle and KenKen for Kids on Kindle.

Griddlers for Kids … JUST $0.99!!!

Remember, there is also a paperback book with Picross puzzles for kids:

As a small gift for you, I’ve prepared an odd-even sudoku variation puzzle. It’s not the first odd even puzzle I ever posted, but it is the first plain odd even sudoku.

And to spice things up a little bit, this is a very difficult odd/even sudoku! It requires you to use the swordfish solving technique! Usually, odd even puzzels are quite easy, but this particular one is rather fiendish! It starts off easy, but then… well, see it for yourself!

Oh… and as you may have noticed… all puzzles are now “facebook free” and they will stay that way, for as long as those folks who do have facebook keep clicking on the “like” buttons. It is not required any more, but it would be nice if you did “like” the free puzzles you download!

Have a nice one, folks!

Odd Even Sudoku for December 25, 2012 – Difficulty INSANE

Click on the puzzle thumbnail to access the puzzle.

So, this is a collection of 100 puzzles specifically designed for children from 6 years of age up to early teens.

Inside, there are classic Sudoku puzzles of different sizes, from 4×4, over 6×6 and 8×8 all the way up to 9×9. Mostly, the puzzles are 6×6 and 8×8.

Further, there are some sudoku variations: diagonal sudoku and odd even sudoku, in same sizes.

So, what are you waiting for? It’s a nice gift for your child and it will develop their cognitive skills…

and it’s JUST $0.99!!!

Remember, there is also a paperback book with Sudoku puzzles for kids:

However, both these Kakuro books are very special. My first Kakuro book contains 200 puzzles. First 150 Kakuro puzzles are standard Kakuros, including some big ones (up to 20×20) and the final 50 puzzles are Kakuro variants, which is something not found in any other Kakuro book!

The second Kakuro book was published just recently. Again, it contains 150 Kakuros (Cross Sums), but it also contains 50 KENKURO puzzles, which should also be called Cross Sums+Cross Products+Cross Divisions+Cross Subtractions.

This second collection of Kakuro puzzles is also available as a Kakuro game on Kindle!

Speaking of Kakuro games on Kindle, there is also an introductory game of Kakuro for Kindle, with somewhat easier puzzles:

I really think this is the best collection of my puzzles. It contains 14 different variations of puzzles:

• Classic Flower and Outside Sudoku
• Diagonal Flower and Outside Sudoku
• Jigsaw Flower and Outside Sudoku
• Consecutive Flower and Outside Sudoku
• Non-Consecutive Flower and Outside Sudoku
• Odd-Even Flower and Outside Sudoku
• Hyper Outside Sudoku (Windoku)
• Outside Twodoku (Gattai-2)