Daily League #62: Mathrax Sudoku

This is the fourth and last puzzle in the 'Latin Squares Sudoku' series. This week it is a Mathrax Sudoku. Originally I had planned a Kropki Sudoku, but after the GP I wasn't really in the mood of writing one. So instead I opted for a Mathrax Sudoku. This type has been a bit of a nemesis with me but the most recent one I actually managed to solve.

For the design I wanted to make two lines containing each type of clue once. I think it looks pretty nice. I needed two extra clues for uniqueness. It is not really a hard puzzle, especially compared to some other Sudokus on my blog. It should still be fun to solve. Enjoy.

Rules for Sudoku

In this Sudoku some intersections of the grid lines are marked by a number and an operator (+, -, x, /) in a circle. The number is the result of the operation, applied to both pairs of diagonally opposite cells. An "E" in the circle indicates that all four adjacent digits are even, while an "O" indicates that all four adjacent digits are odd.

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Puzzle #188: Capsules

This is the sixteenth and last practise puzzle for this year's UKPA Open.

This type is the only one that actually fills a polyomino in the end. I've written enough of these. I always enjoy solving them. It's a simple type. This is a smaller puzzle. I find it pretty handy that both 7x7 and 8x8 grids become divisible into pentominos by taking away the corner.

Rules for Capsules

Puzzle #187: Magic Snail

This is the fifteenth practise puzzle for this year's UKPA Open.

I wanted to include a Latin square type puzzle, but many don't work that well with the digits 1-4. I needed a type that used empty squares to get a workable puzzle. Magic Snail seemed to fit the bill. I used to always have trouble with these puzzle. But since designing a few of these I got a bit more the hang of them. It's important to keep good track of the number through the outside few rows as the ordering forces a lot. It limits the placement of certain numbers in particular cells. This puzzle is not overly hard, although I accidentally sent it out with a missing clue at first. That made testing tricky. With the clue it's not the hardest.

Rules

Write the digits 1-4 once in every row and column (1-3 in the example). When traveling from the left top corner to the centre you should encounter the digits 1-4 four in order: 1-2-3-4-1-2-......-3-4.

Example

 

Puzzle

 

 

Puzzle #186: Neighbours

This is the fourteenth practise puzzle for this year's UKPA Open.

I'd never written these puzzles before. I've solved enough though. In my design I tried to form the solution form a few strategically placed digits. I think this solve worked out well, but I could probably design much trickier puzzles in this genre. It's sometimes just hard to keep track of everything. It's easy to run into no solution moments.

Rules

Place the number 1-3 trice in each row and column (1-2 twice in the example). Digits in grey cells can't share an edge with an equal number. Digits in white cells must share an edge with at least one equal number. All grey cells are given.

Example

 

Puzzle

 

 

Puzzle #185: Sum Sweeper

This is the thirteenth practise puzzle for this year's UKPA Open.

I originally intended to make puzzles that required you to fill dominoes, triominoes, tetrominoes and pentominoes. But I couldn't actually find or think of any good type for everything. There probably are types that would fit the bill. So instead I just went for a simpler way and use the number 1-2 through 1-5 for the four types.

The problem was there aren't many types that use the numbers 1-2. So I cheated a bit and co-opted the Double Minesweeper genre for this purpose. A little change of name and it makes more sense. This puzzle is pretty hard and stumped some of my test solvers. But there's a really nice logic path to find through this puzzle.

Rules

Place the numbers 1 or 2 in some cells. Clues in grey cells indicate the sum of the digits in the white cells around it.

Example

Puzzle

 

Daily League Sudoku #61: Easy As ABCDEF Sudoku

This is the third puzzle in the Latin Squares Sudoku series. This week again a familiar variant. Easy As puzzles are one of the more standard Latin Square puzzles at WPCs.

I always like to write larger Easy As puzzles with numbers as it gives a bit more freedom in designing the puzzles. It's always hard to see whether or not you can get the puzzle in the centre if you can only give the outside clues. I have seen a few larger puzzles with standard clues, but there aren't that many grids that qualify for a unique solution.
I looked for a nice opening for a while. I think this one works pretty well. With the regions it opens up a lot of new openings to try out. I picked the layout of the letters at the start and was trying to keep all number 1, 2 or 3. But in the end I couldn't find a unique solution once I got to the end without using a 4. This didn't really hinder the path of the puzzle much, so I am happy how it turned out. Enjoy.

Rules for Sudoku

Place the letters A, B, C, D, E and F once in every row, column and marked 3x3 area. Clues on the outside indicate the position of that letter in that row or column when looking from that side. E.g. A3 indicates that A is the third letter seen from that side.



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Puzzle #184: Pentominous

This is the twelfth practise puzzle for this year's UKPA Open.

This was the simplest choice for the pentomino division. I like these puzzles. I wrote a few for the Dutch puzzle association, tow of which have appeared on the site so far. Most these were tricky though, so I tried to keep the puzzles a bit easier. There's a few little insights needed to solve this puzzle, but I think it solves nicely though.

Rules:

Divide the grid into pentominos, so that no two pentominos of the same shape share an edge. Rotations and reflections are considered the same shape. Letters in the grid indicate that this cell is part of a pentomino of that shape. Pentominos may contain multiple letters or no letter at all.

Example

Puzzle

Puzzle #183: L-Dissection

This is the eleventh practise puzzle for this year's UKPA Open.

I had a lot of options for tetromino division. There were a few genres from the previous WPC I considered. In the end I wen to a type I don't see that much anymore. When I first started puzzling I would see this genre more often. The rules are pretty simple, but there's not very much room for variation. This puzzle has a tricky opening, but after that it shouldn't be too hard.

Rules:

Divide the grid into L-tetrominos. Each tetromino must contain exactly two circles.

Example

Puzzle

Puzzle #182: Sandwich

This is the tenth practise puzzle for this year's UKPA Open.

I couldn't think of any triomino division puzzles directly. I knew there were domino type puzzles with triominos, but that seemed a bit weird considering I already had dominos. Then I remembered the Sandwich genre, which I had used in the 2014 countdown. I actually liked writing that, so I gave it a go. I think the puzzles actually came out pretty well. There are no real hard deductions in this puzzle, but it's a matter of looking at the right places to make progress.

Rules:

Colour some cells black. Black cells are not allowed to share an edge. Divide the remaining white cells into triominos. Each triomino must contain exactly one digit. This digit indicates how many black squares it shares an edge with.

Example 

 

Puzzle

 

 

Puzzle #181: Dominoes

This is the ninth practise puzzle for this year's UKPA Open.

The third set was all division puzzles. Domino and pentomino were quickly chosen. Tetromino had a lot of options, while triomino was hard to find something interesting.
Dominoes was the most obvious genre. this puzzle caused some issues for my testers. This kind of opening is actually something I like to put in my dominoes puzzles. Once you find it, it runs pretty smoothly.

Rules:

Divide the grid into dominoes, so that each of the given pairs of numbers appears in exactly one domino.

Example

 

Puzzle

Daily League Sudoku #60: Doppelblock Sudoku

This is the second puzzle in the 'Latin Square Sudoku' Series. I've always liked this genre. Nine by nine puzzle are normally pretty hard to accomplish, but it's possible. Adding the regions makes it much easier to construct.

This variant is pretty similar to Between 1 and 9 Sudoku, except for the fact that you aren't forced to give a given. I tried to use an opening that takes the regions into account. This puzzle shouldn't be too hard. I actually had a harder version of this puzzle, but it was a bit too much in my opinion. I didn't even have an option to make it easier without ruining most of the puzzle. I hope it's fun.

[Edit: Puzzle fixed. I made an error, forgetting 7 could be a single digit sum.]

Rules for Sudoku

In this Sudoku you have to blacken two cells in every row, column and marked 3x3 region. Then you have to place the digits 1~7 once in every row, column and marked 3x3 region. Numbers on the outside indicate the sum of the digits in between the black cells in that row or column.




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Puzzle #180: Slitherlink; Filled Loop

This is the eighth practise puzzle for this year's UKPA Open.

This is what I feel is another inherently hard type. So I tried to at least create a few openings that were all based on purely Slitherlink logic. there is a point in the end usually where you aren't as free in choosing your Slitherlink clues as you still need to fit in all pentominos. I think in the end this one gets a bit harder, but if you take into account the "no three can meet" rule, you should still be able to work through.

Rules for Slitherlink

In this Slitherlink the loop has to be completely filled with the given pentominos. Each pentomino must be used exactly once. They may be rotated and reflected. Pentominos may only touch each other by a single edgNowhere do three or more pentominos meet at a point.

Example

Puzzle

Puzzle #179: LITS

This is the seventh practise puzzle for this year's UKPA Open.

If I've written more of the same puzzle type, I always find it hard to think of an opening. Usually in LITS I end up just putting down a few nice looking rooms and see if there's any interaction that I like. This combination of the letter LITS seemed to work for well. The end result worked pretty well, although it took a while to get it unique.

Rules for LITS

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Puzzle #178: Tapa; Triomino

This is the sixth practise puzzle for this year's UKPA Open.

In my TVC practise series, I have become pretty proficient in writing Tapa variants. Usually my puzzles are on the harder side. Thus is won't be overly surprising that this is also a bit of a harder puzzle. This puzzle has a single opening and it's important to find it as I don't think there is any other way through it.

Rules for Tapa

In this Tapa, you must be able to divide the wall into the given triominos.

Example

Puzzle



Puzzle #177: Nurikabe; Domino

This is the fifth practise puzzle for this year's UKPA Open.

This section came about because I wanted to include some common types, while still falling within the theme. I was familiar with three variants of common type that required division into polyominos. So this was easily collected.
I haven't seen that many Domino Nurikabes, so my first go was just checking out what I could do with the genre. The opening was pretty quickly set up. The middle and end game was where it gets tricky. It all works out logically, but it's not too obvious on first sight. It took a while to get the wall to behave properly.

Rules for Nurikabe

In this Nurikabe, you must be able to partition the stream into non-overlapping dominoes.

Example

Puzzle

Daily League #59: Skyscrapers Sudoku

For the month of February the theme will be Latin Squares Sudoku. This might sound like an odd name as every Sudoku is a Latin Square. But what I mean by this is that every Sudoku will be a Sudoku variant of a Latin Square logic puzzle.

The first one is a Skyscrapers Sudoku. Skyscrapers is one of the most used Latin Squares types. Pretty much every WPC I have been to has had at least one. It's a simple idea that can lead to a lot of different puzzles. I think it's the first time I've actually written a Skyscrapers Sudoku, although I have written many Skyscrapers. You can more easily run into unforeseen uniqueness issues with the Sudoku regions added. I had a few puzzles end up having no solutions. I had to tweak the layout a bit. I originally had 4567 on the left side and 456 on the right side, but nothing nice came out of that. The final puzzle should be fun to solve.

Rules for Sudoku

In this Sudoku digits represent Skyscrapers of that height. Clues on the outside indicate how many skyscrapers are visible in that row or column when looking from that side. Larger digits block the view of smaller digits.

Puzzle #176: Pentomino In A Box

This is the fourth practise puzzle for this year's UKPA Open.

Originally this was going to be Pentomino Areas. But when I remembered this type, I had the option to push that down to Tetromino Areas. The first puzzles of this type I've seen are form Richard Stolk. I always find them a bit tricky. I was a bit afraid including this type as I thought they might turn out too hard. I wrote a number of these puzzles and selected the two I thought were easiest. This is the hardest of the two because it has a bit narrower a path. It also felt a bit different than I normally encounter in this type. I thought this was actually easier than normal.

Rules:

Place the given pentominos in the grid so they don't touch each other, not even diagonally. Pentominos can be rotated and reflected. Each black-bordered region must contain three coloured cells that belong to two different pentominos.

Example

Puzzle

Puzzle #175: Tetromino Areas

This is the third practise puzzle for this year's UKPA Open.

The first time I wrote this was for the 2014 Polish Championship Team Round. It was a simpler variant of the more common Pentomino Areas. Originally I was going to use LITS for this type, but I liked that better in the second group. This was the second type I thought of. This puzzle is the harder of the two puzzles. Neither is overly difficult. If you see the opening of the puzzle it should cause no problems.

Rules:

Place the given set of tetrominos in the grid so that they don't touch each other, not even diagonally. Tetrominos may be rotated and reflected. Each black-bordered region must contain a single tetromino.

Example

 

 

Puzzle

 

Puzzle #174: Trio Cut

This is the second practise puzzle for this year's UKPA Open.

I saw this type the first time in the No Numbers test at LMI. I have good memories of it as that's the only test I have ever won. This puzzle is definitely the harder puzzle. The first one I played around a bit with how the type worked. For this one I tried to find a bit more tricky an opening and path. I think it worked out well.

Rules:

Colour some cells so that they form triominos. Each triomino must be cut twice by a black border. Different triominos must not touch each other by an edge. Each black-bordered region must contain exactly three coloured cells. Cells in the same region may belong to the same triomino.

Example 

Puzzle

 

 



Puzzle #173: Norinori

This is the first practise puzzle for this year's UKPA Open.

This is the first Norinori puzzle I have ever written. I wanted to avoid using a domino region as an opening. This is one of the two I found. It is also the harder of the two. This puzzle is pretty hard as there are some key deductions to be made in the middle. It wasn't something I had used myself in a Norinori puzzle before.

Rules:

Colour two cells in each black-bordered region, so that each black cell shares an edge with exactly one other black cell. Black cells may touch within a region, but don't have to.

Example

Puzzle