Saturday, 23 February 2013

Daily League Sudoku #5: Scattered Sudoku

This is my fifth Sudoku for the Daily Sudoku League. The last week so far has featured a Counting on Line Sudoku by Seungjae Kwak, an Equal Sudoku by Christoph Seeliger, a Between 1and 9 Sudoku by Prasanna Seshadri, a Fortress Sudoku by Bastien Vial-Jaime, a Little Killer by Rishi Puri and an Odd Sudoku by Tom Collyer.
This week I've gone for a simpler and more familiar variant. Scattered Sudoku is just a Jigsaw Sudoku with one non-contiguous region. The puzzle has only 17 clues, which is what I like about Jigsaw Sudokus. I like to get the amount of clues down to 20 or less, which is something I wouldn't get done in Classic Sudokus. The solve gets a bit trickier towards the end, but nothing overly difficult. It's in my opinion easier than the last two Sudokus I have posted. Hope you all enjoy them

Lastly, here is the latest PDF-file.
Week 5

Rules for Sudoku

This Sudoku has one non-contiguous 9 cell region, marked by the grey cells.

Thursday, 21 February 2013

Puzzle #159: Capsules

This is a simple puzzle idea that can leave for really tricky puzzles. Most puzzles use similar techniques, except the way you employ them can make a puzzle far trickier. The grid size is a bit limited as the total number of cells has to be divisable by 5. But you can easily change certain sizes in nice ways to valid size. Leave out the center cell in a 9x9 grid, or the four corner squares in a 7x7 or 8x8 grid.
The last puzzle I post here was meant for a puzzle championship, but tested too hard, just like Tuesday's Ripple Effect puzzle. As this would be the first one I posted here, I added two extra smaller puzzles just to prepare people for the harder logic in the last puzzle. Both these smaller puzzles use a key part of the solving logic for the larger puzzle. Hopefully they help and you will enjoy all puzzles.

Rules for Capsules

Puzzle #1

 Puzzle #2

Puzzle #3

Rules: Capsules

Place the digits 1~5 once in every blackbordered region. No two equal digits can touch eachother, not even diagonally.

Tuesday, 19 February 2013

Puzzle #158: Ripple Effect

This is a puzzle originally intended for a puzzle competition, but testing came up with too high times so I'm posting it here now. I know it's different from my normal clueless ones, but there's a reason they were there. You might be able to figure out why later in the week. I think it still solves really nicely and has its tricky spots. A lot of the solve is very similar to my previous puzzles andthere is still a very directed path to the puzzle. I think I will always have trouble writing Ripple Effect puzzles that are more suitable for competition as there is a lot of fun logic to exploit, which is pretty tricky. I could of course put in far more smaller cages, except that is really not very fun to write for me. Anyways, enjoy the puzzle.

Rules for Ripple Effect

Saturday, 16 February 2013

Daily League Sudoku #4: V-Day Sudoku

This week was Valentine's Day, which has influenced a lot of puzzles this week.
My Sudoku is inspired by the abbreviation for Valentine's Day, which seems to be used more often these days, namely V-Day. That's why my Sudoku is themed around the number 5 or V in Roman numerals. It's basically a simple variation of XV Sudoku, except I changed the X pairing of a sum of 10 to a pairing of a difference of 5. The only real difference in the solve is that you don't know whether a mark is a sum of 5 or a difference of 5. As a further theme, the givens spell out the date of Valentine's day: 14-2. For Americans who feel the date is written wrong, you could rotate the grid 180 degrees and spell out 2-14 in the same squares that are filled now and still solve it in the same way. The switching of the places for 1 and 4 doesn't matter and keeps the puzzle unique, but the solution does change a bit.
The puzzle is moderately difficult. Not too difficult, but you have to remember well that all hearts are given.

Rules for Sudoku

Everywhere two adjacent digits have a sum or a difference of 5 a heart is given.

Thursday, 14 February 2013

Puzzle #157: Tapa Special

As I've mentioned before, each year I make a special puzzle for my girlfriend for our anniversary. Earlier examples include my Quattro Stagione and LITS Cube puzzles. This year I went for a big Tapa puzzle. It's her favourite puzzle type, so I thought I'd have a go at it. It was an ambitious project that didn't go without its problems. The first draft ended up having about 8 errors in various places. I eventually removed all but one when I had it tested, which brought about one last bad deduction on my part, which I had missed. Eventually I got it fixed and this is the result. My girlfriend is currently still working on it, but she gave permission to share it with you today.
I've made it available as a PDF through Google docs. This is because I'd advice printing it and I scaled it down in the pdf so it prints easily. It also includes all rules and the layout, to make the solving easier. It's a challenging puzzle and I think it helps being able to visualise the whole puzzle.

Below will be the same information as in the PDF, for anyone preferring to solve it on the computer. This includes a full size image. If there are any questions about the rules, please feel free to ask.

Tuesday, 12 February 2013

Polish Online Qualifiers: Magnets and Yajilin

The Polish online qualifiers were held December last year. You can find the puzzles and sudokus here: Puzzle Set 1, Puzzle Set 2, Sudoku Set 1, Combination Set. I'm not sure on the details what each set was used for as I can't read Polish. I contributed 2 puzzles, which can be found in the first Puzzle Set. They are a Yajilin and a Magnets puzzle. I tried to make them easy, but I was told after the testing that the Magnets puzzle still wasn't very easy. I seem to not able to write easy Magnets puzzles. I'm guessing some of the deductions just come standard to me but they don't come standard to others. They're both still nice puzzles, so hope you enjoy them too.

Rules for Yajilin

Rules for Magnets

Saturday, 9 February 2013

Daily League Sudoku #3: Battenburg Sudoku

Last week I didn't provide a puzzle as Stefan Heine had a puzzle ready, so I gave up my Saturday spot. This week there is another Sudoku by me. This is a Battenburg Sudoku, which is a Sudoku type I came up with.  The name comes from the Battenburg markings, although it stays more in my mind for Battenberg cake, which is a checkerboard pattern. In this puzzle everywhere 2 odd and 2 even digits form a checkerboard pattern, a mark is given. The opening of the puzzle I have in mind is a bit puzzly and might trick up some Sudoku-solvers. That's why I have made a second puzzle that should help you realise part of the logic involved in the opening, which is posted here. I hope you enjoy it, it was fun to make at least.

Lastly I'll provide three links for the puzzle files of the last three weeks.

Week 2
Week 3
Week 4

Rules for Sudoku

In this Sudoku, everywhere 2 odd and 2 even digits form a 2x2 checkerboard pattern, a Battenburg marking is given.

Click to enlarge

Friday, 8 February 2013

Puzzle #156: Battenburg

This puzzle is as preperation for my next Daily League Sudoku. I was a bit afraid part of the logic might trick up some people, so I figured I'd make something nice to practise it with. I think the puzzle turned out really nicely, with the asymmetric clues. It should be fun to solve, even though the logic might be a bit repetitive.

Rules for Battenburg

Place 5 black circles and 4 white circles in every row, column and marked 3x3 area. Everywhere 2 black and 2 white circles form a 2x2 checkerboard pattern a Battenburg marking is given. Some circles are already placed.