Wednesday 30 December 2015

TVC XVII Practise: Part 1

This is the first selection of practise puzzles for the upcoming TVC XVII. I only came aware this was starting again today, so I'm trying to get all puzzles out by Friday. This post will feature the first five puzzles.

The first puzzle is a Peers Tapa. I like the idea of this variant. I always enjoy Tapas that have the same sum in symmetrical clues. This variant forces that. The puzzle turned out reasonably well. It's one of the easier practise puzzles.
The second puzzle is a Tapa Skyscrapers. The variant can drive a lot of the puzzle, so I tend to just place some random, but nice looking, Tapa clues and make the variant drive the rest of the puzzle. I think it worked out well in this puzzle. It's not an overly hard puzzle, but you have to understand how to use the variant.
The third puzzle is a Knapp Daneben Tapa. I always have trouble with 1s turning into 0s when designing Knapp Daneben puzzles. I tried to avoid the issue as much as possible. My personal goal when designing Knapp Daneben puzzles is always to try to only use valid Tapa clues and not use combinations of digits in a cell that would not be allowed in a normal Tapa.
The fourth puzzle is an Outside Tapa. The first Outside Tapa I wrote I used a lot more Tapa clues, but I went for a lower number of clues this time and have the variant drive the solve a bit more. It turns out that using more equal symbols reduces the need for clues. I think it turned out well. This is probably the hardest puzzle in this set.
The fifth puzzle is a Tapa Magic. I'm not that much a fan of this variant. I always feel I have to use too many clues, because the restrictions won't allow it to be unique otherwise. It's still a nice puzzle and shows some of the tricks in this variant.

I hope these are helpful. Enjoy.

[Edit: Tapa Skyscrapers fixed.]

Puzzles can be found below.

TVC XVII Practise: Introduction

It seems 2016 is again a Tapa Variations Contest and Classic Tapa Contest year. That means that I'll actually have to defend my Tapa Master title I won in 2013 instead of the coasting on the honour without little effort. The CTC will run daily over 50 days from the 2nd of January 2016 till the 22nd of February 2016. The TVC will run in four contests over weekends between the 2nd of January 2016 and the 22nd of February 2016  The first of these contests, TVC XVII, will run from the 2nd of January 2016 till the 4th of January 2016.

TVC XVII will contain 10 variations. These variations are Alternative Tapa, Tapa with Borders, TAPA LOGIC, Peers Tapa, Tapa Skyscrapers, Make Room For Tapa, Tapa Star, Knapp Daneben Tapa, Outside Tapa and Tapa Magic. These are all variations that have previously appeared in other TVCs. So for practise you can check out older TVC's. In this post I will post the puzzles I shared before as practise for older TVCs. I will also be posting new examples for all these type in other posts. I hope they will all be useful in preparation. But not too much as I'd like to be the first to successfully defend a Tapa Master title.

Puzzles can be found below.

Sunday 27 December 2015

Daily League #53: Quad Division Sudoku

This is the fourth and last Sudoku in the 'Quad Sudoku' series. It's as far as I know a new variant. I wish I could check somewhere what variants have been done already. I though it would be nice to have a variant where the four cells were treated as two two-digit numbers. I considered turning the Diagonal Difference puzzle from instructionless round of the last WPC into a Sudoku, but I had already made a Quad puzzle with differences. Then I figured I could do something similar with division.
I just started playing around with a few placements and I noticed that the clues carry a lot of impact. They give you a lot of information and you get placements pretty quick. So I figured it should be possible to make one without any givens. I always enjoy trying to turn out Sudokus without any givens, which most people doing my Daily League puzzles must have noticed. This puzzle had an opening constructed pretty quickly. The problem of course was to get it unique with only valid clues. I had a few puzzles that were close but I couldn't get any valid clues in anymore to make it unique. After a few tries, this puzzle came out. I don't think it's overly hard, but it does involve a bit of careful calculations to make sure you don't make any errors. There's very little chance to track back.

Rules for Sudoku

In this Sudoku, a number on a grid point indicates the result of dividing the two-digit number formed by the top two digits by the two-digit number formed by the bottom two digits. Both two-digit numbers have to be read from left to right.

Click to enlarge

Sunday 20 December 2015

Daily League #52: Quad Max Sudoku

This is the third puzzle in the 'Quad Sudoku' series. This time once again a common variant. I picked this type as it's not an arithmetic variant and many of the Quad variants are arithmetic in nature. It's also a type that I enjoy solving.
In the design I wanted to see how far I could get with just Quad Max clues. I knew that eventually had to use givens as there is no way to differentiate between 1s and 2s with these clues. I think the design worked out well. The puzzle in the end has four givens. One of them is not necessary for uniqueness, but I wanted to keep the symmetry and it didn't ruin the solving path. The last few digits are a bit tricky, but I thought it was okay with so few digits remaining.

Rules for Sudoku 

In this Sudoku, an arrow on a grid point points to the highest digit in the four cells around it. Digits may repeat around an arrow, but the highest digit is always unique.

Click to enlarge

Sunday 13 December 2015

Daily League #51: Quad No Difference Sudoku

This is the second puzzle in the 'Quad' Sudoku series. As far as I'm aware this is a new variant. It's the first puzzle I wrote for this series. I just thought it would be better to open the series with something more common. I thought the variant worked pretty nicely.
The design was a bit tricky. I had a different layout in mind, but I couldn't find a way to get that layout unique without giving digits around a clue. That was something I was trying to avoid as I think these Quad Sudokus look nicer when there are no digits given around the Quad clues. I changed the layout a bit in the left top and right bottom nonet. Originally the right bottom nonet was to get a Quad clue as well, but there was no way to force the 5 with such a clue. I needed that 5 for uniqueness. I still think it's a nice looking puzzle and it should be a good solve.

Rules for Sudoku

In this Sudoku, a clue given on a grid point indicates that no two of the four digits around it have this difference. E.g. a 3 clue indicates that no two of the four digits around it have a difference of 3.

Click to enlarge

Sunday 6 December 2015

Daily League #50: Quadruple Sudoku

This month's theme is Quads. They will all be variants that with clues on grid points, that give information about the four cells around it. This set will contain two known variants and two new variants, as far as I'm aware. The choice for this theme came because I had an idea for a variant. I made a Sudoku with it and I think it turned out nicely. I figured it would make a good theme as there are many variants that use such a clue.
The first Sudoku is the most common variant. It's a variant I've written once before, but never for the Daily League. It's what I consider a classic variant, because there are no alternative clues in it. I wanted to make one without any overlapping clues. It turned out nicely in my mind.

Rules for Sudoku

In this Sudoku digits given on a grid point indicate the digits in the four cells around it.

Click to enlarge