Puzzle 195: Terra X

Here’s a puzzle from my preparation for WPC 2019 that I don’t believe I’ve posted yet. It’s also sort of a practice puzzle for the upcoming first round of the 2020 Puzzle GP, which features the variant Terra XX.

Rules Place numbers in the empty cells, from the range 0-9. Same numbers can’t be adjacent (but may touch by a corner). Wherever four cells meet at a vertex (marked by a black dot), the sum of the numbers in those cells must be 10.

Puzzle 194: Double Choco

Here’s another Double Choco, probably of similar difficulty to the New Year’s puzzle. I made this one as a “secret solver” present to a user going by the handle “taus” on the Puzzler’s Club chat; the layout is based off their avatar. (There’s a second partial attempt at theming this puzzle that’s a bit less in-your-face.)


Puzzle 193: Double Choco

A puzzle to welcome 2020. This is probably not the first Double Choco puzzle you want to solve.

You can find some easier puzzles in the puzz.link db.


Rules Dissect the grid into regions. Each region consists of a dark piece and a white piece; these pieces are connected edge-wise, and they must have the same shape, up to rotation and reflection. A piece may contain any number of clues; these give the size of the piece.

puzz.link Christmas update: pzprjs release, and introducing the puzz.link database

It’s still nowhere near where I want it to be, but I imagine some of my readers are in desperate need of puzzles over the holidays. So I decided to finally announce the puzz.link database – see below. But first:

robx/pzprjs v0.12.0

It’s been a while since I made a proper release for my fork of the pzprjs puzzle applet. Since releasing v0.11.1 back in April 2019, some of the notable changes have been:

  • add 9 new puzzle types: Aquarium, Castle Wall, Compass, Curve Data, Double Choco, Geradeweg, Heteromino, Pencils and Regional Yajilin
  • there’s now a page listing the rules for a type by example of possible errors, e.g. for Double Choco
  • a variety of improvements to individual types, e.g.:
    • Country Road now has a variant rule to permit empty rooms
    • for puzzles like Heyawake, you can now shade-blank across shaded cells (with mouse)
    • Star Battle now allows placing auxiliary dots (e.g., to mark when a star is in one of two cells)
    • Kakuro now supports blank clues
    • for moving puzzles like Herugolf and Satogaeri, movement is restricted to straight lines

Check the Changelog for the full list. Thanks to all contributors, particularly to Lennard Sprong!


At puzz.link/db, you can find an index of publicly shared puzzles from all over the internet. In its present form, it started out as a tool for me to keep up with the flood of excellent puzzles shared on twitter. It aggregates puzzle links (to pzv.jp and puzz.link) from twitter and several puzzle blogs, and lets you track which ones you’ve solved, as well as providing some ways to filter (e.g. by puzzle type or author).

If you miss nikoli.com or croco-puzzle.com, this might help fill the gap. Let me know what you think! I hope it doesn’t fall over from the mass of new users.

Puzzle 190: Castle Wall

Yet another new puzzle type on puzz.link – many thanks to Lennard Sprong for this and other contributions. I made this puzzle to announce the addition.


Rules Draw a loop from cell center to cell center. Black clues must be outside the loop, while white clues must be inside. Furthermore, Numbers indicate the total number of straight segments in the given direction.

Assorted compass puzzles

To celebrate the release of the puzz.link compass applet, I collected some of my older compass puzzles.

Find more compass puzzles by other authors in the puzz.link database or on Puzzle Square JP.

Puzzles 186-188: Standard / Touching Slitherlink

Here are a couple of puzzles of widely varying difficulty that I made for the hybrid type Standard / Touching Slitherlink that featured in Round 8 (Twilight) of WPC 2019. I could have sworn this variant existed somewhere on the Rätselportal or in the Logic Masters archives, but I couldn’t find it. It’s quite similar in some ways to related hybrids like “Außen-Knapp-daneben-Rundweg”, but has some quite novel features.

Edit Added a clue to the 3s-puzzle to save the intended break-in.

Rules Draw a loop by connecting grid points as in standard Slitherlink. Clues inside the loop act as standard Slitherlink clues (i.e., they count adjacent edges that are used by the loop). Clues outside the loop count how often the loop visits the boundary of the cell, as in Berührungsrundweg (e.g., a clue 4 means that the loop uses all of the cells corners but none of the sides).
Or see the instruction booklet.

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