# Puzzle 156: Killer Sudoku

Next weekend I’m running a pure Killer Sudoku contest at logic-masters.de. The idea was to give our Killer Sudoku experts a chance to shine. It’s 9 puzzles in 90 minutes from 6 authors, see the instruction booklet for further details. Thank you to Tom Collyer, Stefan Heine, DavidMcNeill, Eva Schuckert and Bernhard Seckinger for their contribution!

To get you in the mood, here’s one Killer Sudoku.

Rules Solve as a regular Sudoku. In addition, some cages are given. The cage clues indicate the sum of the digits within the cage. Digits can’t repeat within a cage.

# Puzzle 155: Minesweeper-Tapa

Here’s another puzzle I made in preparation for the recent Logic Masters. It’s a Minesweeper Tapa, a type from the Tapa round on the contest.

In other news, results have now been posted: https://logic-masters.de/LM/2018_e_tabelle.php. (It seems linear time bonus really isn’t the right choice where players finish after a fraction of the round: On round 6 I took 3.5 minutes compared to the next player’s 5 minutes, for a factor 1.06 in points.)

Rules Solve as a regular Tapa, except the clues just specify the total number of shaded cells in the surrounding cells, as in Minesweeper.

# Puzzle 152: Masyu No-Touch

Another one for the GP. This is a Masyu with the extra rule that unused cells can’t touch by edge.

Solve and check your solution here, or use PZV (but that doesn’t verify the no-touch rule).

# Puzzle 151: Skyscraper-Nurikabe

We continue with the regular puzzle-a-month-on-the-first-of. Here’s a Skyscraper-Nurikabe, a practice puzzle for the upcoming Indian GP.

Rules Solve as a regular Nurikabe. Additionally, some skyscraper clues are given outside the grid. For these, consider the blocks of adjacent shaded cells within the corresponding row as skyscrapers with height equal to the number of cells in the block.

Or check the instruction booklet which includes an example.

You can solve online (of sorts) and check your code here.

# Puzzle 144: Easy as ABC (Zehnkampf)

Last weekend I took part in a puzzle decathlon, run by Berni of croco-puzzle. That involved 10 rounds modelled on the athletics decathlon, where the running events mapped to puzzle solving (the hurdles were possible broken puzzles), jumping events mapped to puzzle creation, and throwing events mapped to optimization puzzles. A lot of very original ideas, and overall it worked very well. Puzzles and results are available at logic-masters.de.

One of the construction rounds, the Pole Vault, gave you three tries at constructing a high-scoring Easy as ABC puzzle: Before each attempt, you chose a grid size, then had 15 minutes to extend a partially clued puzzle of that size to a correct puzzle. The score was calculated by subtracting twice the number of added outside clues, five times the number of inside clues and once the number of diagonal adjacencies in the solution from ten times the number of rows/columns. I had a rough start there, but ended up with a pretty good third try, with this 8 by 8 puzzle.

Rules Place letters A-C into the grid so that each letter occurs once in each row and column. Clues indicate the first letter in the corresponding row or column.

# Puzzle 143: Nanro Signpost

Here’s a Nanro Signpost.

Rules Shade some cells, so that all shaded cells are connected, and such that shaded cells don’t fill any 2×2 square. Clues indicated the number of shaded cells in an area; each area must have at least one shaded cell. Whenever two shaded cells touch across walls, the number of shaded cells within both areas must be different.