DJ Ape .Net – The Home of Perfect Sudoku

Here is something that all true Killer Sudoku fans will surely enjoy… a compilation of your favorite Killer Sudoku puzzles of all sorts and sizes!

Most types of puzzles printed in this book cannot be found elsewhere! Needless to say, all puzzles are unique and never published before.

(click on the cover page to go to lulu and buy!)

US $7.50 or £5.34 or €5.81 (PDF e-book)

(payable by PayPal or credit card)

101 puzzles in 12 different categories, so what you get is this:
- 20 classic Killer Sudoku
- 20 Zero Killer sudoku
- 10 Killer X
- 10 Killer Sudoku with +, -, * and /
- 10 Killer TwoDoku
- 5 Killer Samurai
- 5 Flower Killer Sudoku
- 5 Butterfly Killer Sudoku
- 5 Twin Zero Killer Sudoku
- 5 Odd/Even Zero Killer Sudoku
- 5 Non-consecutive Killer Sudoku
- 1 Clueless Killer Sudoku

Enjoy!

Having perfected my Hitori generator, I’m ready to present you with my first Hitori book.

This book contains 150 puzzles in 6 levels of difficulty, varying in size from 5×5 up to a humongous 20×20! A very detailed introduction with solving strategies and techniques is also given.

(click on the cover page to go to lulu and buy!)

US $5.95 or £4.24 or €4.61 (PDF e-book)

(payable by PayPal or credit card)

Enjoy!

Solving Hitori puzzles is about recognizing patterns. I will show you some examples of those patterns. They can be split into two groups, one of those that depend solely on the initial positioning of numbers, and another group of patterns that depend on the black and white cells which have been painted in the solving process.

One trivial advice that you should always keep in mind: if a cell cannot be black, it must be white! And vice versa. From this comes one simple solving technique: when you conclude that a cell must be painted, circle the numbers in all four adjacent cells to indicate that they must be left unpainted. Now, back to the patterns…

Corners
Check the corners first. Here is an example:

When you have 2 same numbers adjacent to each other in a corner, you can circle at least one other number. Why? It is easy to see that the “1” cannot be black, because one of the “4”s must be black. If the leftmost “4” were black, the “1” would be adjacent to it. If the rightmost “4” were black, the “1” couldn’t be black because those two black cells would isolate the other “4” in the corner, which is against the 2nd rule of Hitori. Got it?


Here are some other similar patterns that occur in corners:
        


And here are some other examples for you to practice:
            

Squeezed in the middle
This is probably the most common pattern in Hitori puzzles.

A number squeezed between two same numbers must be white! If it were black, it would eventually cause two black cells to be adjacent, which is not allowed.
Oh, and don’t be put off by three same numbers adjacent in a row or column. The same rule applies.

Elimination
By the way, once you’ve circled a number, make sure to eliminate all other occurrences of the same number in the same row and column:

No room for three
Another very common pattern is when two same numbers are adjacent to each other and there is another one in the same row/column. Obviously, one of the adjacent “3”s will have to be white (they can’t both be black). Whichever one it is, the 3rd “3” in the same column will have to be black, as you can’t have two “3”s in one column.

Those were the basics. That’s how you start solving any given puzzle. In a few days, I will post some more complex patterns that are used in the more difficult of puzzles.

I promised that Hidoku puzzles will be back in one form or another… and here they are!

When I published Volume 1 of this book I did say that I was a little worried that I’d overdone the difficulty of the puzzles. And rightly so. Your comments did say that some puzzles were too challenging. Therefore, this time I have reduced the difficulty of the puzzles, but only by a notch. So, if you are new to Hidoku, I recommend trying volume 2 before volume 1!

(click on the cover page to go to lulu and buy!)

US $5.95 or £4.24 or €4.61 (PDF e-book)

(payable by PayPal or credit card)

Enjoy!

A little later than anticipated, I’m about to start posting Hitori puzzles on a daily basis.

Since there are already plenty of puzzles being posted daily, I had to drop something. So, the daily Hitori puzzles will replace the daily Hidoku puzzles. Hidoku will be back in one form or another. Stay tuned for updates.

The daily Hitori puzzles will be available from here.