DJ Ape .Net – The Home of Perfect Sudoku

Here is a new variant of Outside Sudoku puzzles: Sudoku Straights.
The rules of Outside Sudoku are explained here.
The rules of Sudoku Straights are explained here.

Now, all you need to do is combine them and apply them both. It’s a rather difficult puzzle (or so I think).
What do you think?

Outside Sudoku Straights for Friday, March 12, 2010 – Difficulty: IQ.

Here is my second Slitherlink puzzle. My solver thinks it’s rather difficult. What do you think?

The rules of Slitherlink (Takegaki, loop-the-loop, loopies…) can be found in my introductory article.

Slitherlink 11×11 for Monday, March 4, 2010. Difficulty: INSANE?

Enjoy and do comment, please!

In case you didn’t see this one coming, well then… you don’t know me and should be coming to this site more often!

Killer TriDoku puzzle: all standard rules of Killer Sudoku apply + of course the TriDoku rules.

Has anyone else published this kind of puzzle until now?

Killer TriDoku for Monday, February 22, 2010. Difficulty: BRAIN
(when you click&download the puzzle it won’t look so blury!!!)

The solution is here

If you can have Diagonal Sudoku or Sudoku X puzzles, why not have a TriDoku X? Although it looks more like a TriDoku *, I decided to keep the “X” in the name. Perhaps it could be called a TriDoku Star?

Whatever you call it, I think the additional rules are obvious: in addition to all the triangular nonets, outside and inner edges, hexagons etc., you now have 3 more lines of 9 cells that must follow the no-repeats rule. Those 3 lines are clearly indicated in the puzzle.

And by the way: I switched the dark gray and light gray cells. I think the puzzle looks better this way. Let me know what you think.

TriDoku X for Thursday, February 18, 2010. Difficulty: BRAIN

I’d like to hear more comments from you! I really need to know how you like these puzzles. If you hate them – tell me. Please!

Here is a puzzle that I think deserves a lot of attention: TriDoku! It’s a great puzzle-type but for some reason it’s very rarely seen in the Sudoku world. I want to change that!

Even though it may not appear obvious, there are 81 cells in this puzzle. And there are 9 nonets. Just like in your ordinary Sudokus. But there aren’t 9 rows and 9 columns. Why? Because the puzzle is triangular!

The rules:
1. There are 9 nonets in forms of triangles. These are drawn with thick lines. All must contain all numbers 1-9.
2. Each edge of the big triangle contains 9 numbers – again, no repeats there either. These cells are shaded in DARK GRAY.
3. There is an INNER triangle, shaded in LIGHT GRAY. Each side of the inner triangle contains 9 numbers. No repeats on those sides, please.
4. And finally: two cells that are touching each other must not contain the same number! Make sure you use this rule! Each cell is touching up to 12 other cells! Be careful!

All solving techniques come from classic Sudoku. Use naked and hidden singles and subsets in nonets and edges. Use interactions between the nonets and the corresponding edges. But finally, you will have to use: the hexagon rule!

The Hexagon rule comes directly from rule number 4. Since two touching cells cannot contain the same numbers, then a group of cells that are ALL touching each other cannot contain any repeats. Simple? Yes. Well then, each hexagon (6 cells pointing to each other) must not contain duplicates, so you CAN use the subsets solving technique, but be careful, there are 6 cells and 9 possible numbers!

Some of the techniques I will explain in detail in the coming days. Now, lets see the puzzle!

Oh, and one quick note: 3 cells are marked half dark gray half light gray. They are not split in any way, they contain one number, but they belong to both an outside edge and an inner edge, so I marked them this way.

TriDoku for Friday, February 12, 2010. Difficulty: THINKER

Comments? Questions? Please!

Another kind of puzzles that I’ve started creating recently… Slitherlink!

These puzzles are also known under many different names. Slitherlink puzzles are not a Sudoku variant. They can be of any size and the rules are:
1. Connect the dots to form a single loop with no points of intersection.
2. The clues given tell you how many sides of each cell belong to the loop. In other words, how many lines there are around the number. If there is no number given, it is unknown (it doesn’t mean it’s zero).

Solving techniques are numerous. I will soon start posting a series of solving methods. But here are a few tips: start with the corners and think. Also, always remember the rule number one: no intersections! This effectively means that each dot has either 0 or 2 lines coming out of it! It can’t have 1 because the loop must be, well, a loop – it must be closed. It can’t have 3 or 4 because that would be an intersection. So it must be 0 or 2.

I’m still working on the difficulty. So your input on the difficulty of this puzzle is appreciated. I believe this one is relatively easy – I still haven’t implemented all solving methods.

Slitherlink 13×13 for Monday, February 8, 2010.

Enjoy and do comment, please!

I don’t think I’ve ever posted a puzzle like this one. Yes it is essentially a Killer Sudoku puzzle. Yes, it’s also an overlapping sudoku puzzle, Gattai-2 (TwoDoku). But it also has some similarity with Calcudoku puzzles, because you must use all four operators (+, -, *, /).

Killer TwoDoku with all ops for Tuesday, February 2, 2010 – Difficulty: BRAIN.

It’s been a while since I last posted a Killer Sudoku variation. As far as I can remember, you folks liked the Butterfly layout of the puzzles, so here is an overlapping, 4-in-1 (Gattai-4), Butterfly Killer Sudoku puzzles.

You can also find these puzzles in my Killer Sudoku Compendium book.

Butterfly Killer Sudoku for Friday, January 29, 2010 – Difficulty: BRAIN.