Puzzle 141: Twin-Detector Sudoku (diagonal)

The WSC 2016 is over. I have a lot of puzzles left to solve, but I’m quite happy with my result (54th in the general ranking, after the 39th official participant, after 89/63 last year). Here’s a puzzle I made to help Martin to prepare to become the King of the Mountains (not sure that helped, considering I didn’t quite have the rules right). Test-solved by the new world champion Tiit Vunk of Estonia. Congratulations to both!


Rules Fill the cells with numbers 1 to 9, so that no number repeats in a row, column or outlined 3×3 square. Whenever a number is equal to the sum of some numbers in a diagonal direction, an arrow is placed pointing there.

(The standard rules also have arrows pointing horizontally and vertically.)

Puzzles 138-140: Not Oasis

I played around with what I thought were the rules to Oasis today, and came up with this variant.

Rules Shade some cells, to leave a connected area of unshaded cells that includes all given numbers and doesn’t cover any 2×2 square. Some shaded cells are given. Numbers indicate how many other numbers can be reached through unshaded, unnumbered cells.

Example (a poor example: shaded cells can be adjacent)notoasis-example

Puzzlesnotoasis-1 notoasis-2 notoasis-3

Puzzle 137: Lamps

Just a tiny puzzle that I made as an example for the croco WPC preparation series. It was a bit too hard as an example; the type seems inherently hard.


Rules Place some lamps in the empty cells around the grid, with brightness 0 to 3. The lamps shine horizontally, vertically and diagonally in eight directions. In each direction, they illuminate as many cells as they are bright. Numbers inside the grid indicate how many lamps illuminate the corresponding cell.

The WPC instruction booklet has an example.

Puzzle 136: External Sudoku

We’re running a small preview series on croco-puzzle for the 2016 WSC and WPC, which will take place in Slovakia soon. We’ll kick it off with an External Sudoku tomorrow. For this, I made an example puzzle which seems worth posting in its own right.


Rules Solve as a standard Sudoku, i.e., fill the grid with numbers 1-8 such that every row, column and outlined area contains each digit exactly once.

In addition, there is a diagonal rectangle of gray cells. Every edge of this rectangle must contain exactly the digits 1-(length of the edge). Diagonally adjacent digits in gray cells must not be consecutive.

Or see the instruction booklet.

Pentomino team puzzle

Here’s a team round I made for the Polish championships earlier this year. It was used for a casual team competition in the evening, between puzzle and sudoku championships.

It’s a two stage puzzle. The first part consists of dissecting some grids to form a set of pentominoes, which are then used as the pentomino set for a big Statue Park puzzle.

The puzzles are designed to be solved with a pair of scissors (i.e., cut up the dissection grids, then place the resulting pentominoes on the statue park grid). If you want to avoid that, you should be able to get a similar solving experience by only marking full pentominoes, and not marking empty cells for the Statue Park.

We went with teams of three in Poland, which is probably the best size for this.

Find the puzzles and original instructions below, or all in one PDF. (The PDF comes with the full Statue Park puzzle, and both halves as individual grids, for A4 printing.)

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