# Puzzle No. 440, 441 : Tapa [Touch and Go]

I’ll just quickly link to a few of my contributions to the recent Czech Team Sudoku and Puzzle Championships.

1. I co-authored a Sudoku team round with Tom Collyer. The round has easy classics, that give some digits which need to be transferred to harder variants. The Weighted Killer, the Outside or Skyscraper, the Rossini and the Battenburg are all written by me. They are all uniquely solvable, without the transferred digits, but obviously, the transferring makes them easier. This Sudoku round is the 6th round, and can be found in PDF numbers 28 and 29 in the Sunday tab of the above link.

2. I wrote two team puzzles, one being an interconnected wall puzzle, a combination of LITS, Nurikabe and Tapa. This puzzle has two versions. The original version included determining where the part-grids go as well as solving them. Based on testing times, I decided to make it easier and gave the positioning of the 9 grids at the start itself. The detailed wall rules and the actual competition puzzle can be found on the Sunday tab of the above link, it is the 6th Puzzle round, which is PDF numbers 35 and 36. There are English rules there too. The original version of the puzzle, with just the layout given and some added logic required in placing the part-grids correctly, is given below.

OriginalWall

3. The second team puzzle was a Loop puzzle. It is a combination of 4 loop types, a Masyu, a Yajilin, a Simple Loop and a Country Road. There’s an added rule that there are certain shaded cell positions given where the loop segment behaviour is exactly the same for all 4 grids. This can be found on the Saturday tab, it is the 2nd puzzle round, PDF numbers 16, 17 and 18.

To today’s puzzles now. I came up with this variant today, and liked it enough to use it in two puzzles. I didn’t really check if the variant exists already, but I can’t remember solving one with these rules.

Rules – Follow regular Tapa Rules. Additionally, no dead-end can ever be a part of a checkerboard pattern. A dead-end is a shaded cell with just one orthogonally adjacent shaded cell, and a checkerboard pattern is a 2×2 area of alternating shaded and unshaded squares. Note : The clue cells are also considered as unshaded cells for the checkerboard pattern.

Rated – Medium (the first one’s on the easy side and the next one’s harder)

Enjoy!

P440

P441