Genre Spotlight 8: Tontonbeya (Puzzles 233 and 234)

Today's genre is Tontonbeya.  It's actually similar to Tetrochain in some aspects: fairly recent Nikoli genre, ported to the puzz.link editor last year, not too many puzzles overall.  Genres involving triangles, circles, and squares are not so common, but they often have fun ideas that aren't really explored by more conventional types.  (That said, they might be a bit annoying to annotate on paper, which might explain why they haven't caught on more widely.)

Rules: In each cell, place either a circle, triangle, or square. Within a region, all instances of a symbol that appears must form an orthogonally connected group. Each group in a region must be the same size. Additionally, each group of a certain symbol must touch exactly one other group of the same symbol across a region boundary.

                   

(Figured I might as well add examples to these posts.  Feel free to prod me if I miss any.)

Genre Spotlight 7: Makaro (Puzzles 231 and 232)

Makaro has had a puzz.link interface for a while, but puzzles in this genre are fairly rare -- there are only about 20 grids on PuzzleSquareJP and about three pages of puzzles on puzz.link (excluding the Nansuke puzzles made using the Makaro editor).  This type is cute, and it has some interactions I don't really see in other number placement genres, but wow it is way harder to construct than I expected.  Thanks be to myamya for extensive help with constructing these, especially the first one.

Rules: Place a number into each cell so that each region contains the numbers from 1 to N with no repeats, where N is the number of cells in the region. Numbers of the same value may not touch one another orthogonally. Each arrow must point to a number which is larger than all other numbers orthogonally adjacent to the arrow.

   

Genre Spotlight 6: Hurdle (Puzzles 229 and 230)

The past few puzzles have been fairly recent inventions, riffing on modern puzzle conventions to create interesting ideas.  Today's type is very different.  It's an old Nikoli type from the mid-1990s and, at the time, was apparently infamous for having a ruleset that was difficult to understand.  I wasn't able to figure it out myself -- it's a weird case where looking at a solved puzzle might not be enough.  But once you realize what's going on ... wow, it's a strange type.  I don't know how much potential it has when compared to some other classic genres, but it has a silly feeling to it (even though it's really a full loop genre with a different presentation).  

Rules: Draw segments on the dotted lines to create a path one square wide that circles through all squares once. This means that every square will have walls in two directions, including the outer perimeter. For each circled cell, count the number of consecutive grid borders which have walls in these two directions, again including the outer perimeter if necessary. Numbers indicate the maximum of these two wall counts.

Genre Spotlight 5: Tetrochain (Puzzles 227 and 228)

Tetrochain is a fairly new type in the grand scheme of things -- it debuted in Puzzle Communication Nikoli (appreciated PCN) issue 181, which released in late 2022.  While the Yajilin-style clues aren't perfect, the idea of a diagonally connected chain of tetrominos is neat, and I wonder if more can be done with this seed.

Rules: Shade some cells in the grid to form tetrominos which do not share an edge.  Clue cells cannot be shaded and indicate the number of shaded cells in the direction of the arrow up to the border of the grid.  Identical tetrominos cannot touch at a corner, and all tetrominos must be connected diagonally (i.e. by corners).

     

Genre Spotlight 4: Nurisquare (Puzzles 225 and 226)

Maybe Nurisquare is less an "obscure" type and more a "new" one -- it was only invented two years ago by internet user machka.  But it's a neat idea!  Natural combination of Nurikabe and Tasquare rules.  Not much else to say.

Rules: Shade some cells so that each orthogonally connected group of shaded cells is in the shape of a square.  Each connected group of unshaded cells must contain exactly one number, the value of which represents the size of the area.

           

Genre Spotlight 3: San-Anko (Puzzles 223 and 224)

The third genre we'll cover is San-Anko!  This type is pretty obscure.  It was originally developed by Nikoli reader Subaru Saito for issue 175 of the magazine, but was rejected for unknown reasons.  (See #12 here.)  Regardless, this type is neat!  It's a bit tricky to make break-ins that aren't <insert break-in to Puzzle 223 here>, but there are some interesting interactions that can occur between different number groups.  (That said, I wonder how much mileage one could get by allowing some of the parameters to be adjustable.)

Rules: Place a number between 1 and 3 in some empty cells.  Numbers must appear in groups of 3 orthogonally connected cells with the same number; different groups cannot touch at an edge.  Clues on shaded cells indicate the sum of numbers in the (up to four) orthogonally adjacent cells.