Fall Sudoku

What is fall sudoku, or autumn sudoku?

Fall Sudoku (autumn sudoku, if that is what you call the season) trades the digits of classic sudoku for nine autumn pictures: maple leaf, fallen leaf, acorn, pumpkin, apple, mushroom, corn, scarf and hot drink. No picture repeats in a row, a column or a box. Everything our 21 picture games have in common, views and levels included, is raked into one pile on the Themed Sudoku page.

Somewhere in late September the evenings draw in, being outside stops being the default, and the indoor season begins. Fall is when puzzles come back. A 6×6 under a blanket while it rains is the season in miniature, and the 9×9 is for the first properly dark evening of the year.

The bigger the board, the more of the set it deals, always from the top. The 4×4 gets the first four: the Maple Leaf, Fallen Leaf, Acorn and Pumpkin. The 6×6 adds the Apple and the Mushroom, and the Corn, Scarf and Hot Drink wait for the 9×9. One name is a stretch: the Acorn is the emoji Unicode names CHESTNUT, which Windows draws as a brown nut with a pale base and no cap. And the Mushroom, a red cap with white spots, is the kind you admire on a walk and never eat.

How do you tell the maple leaf from the fallen leaf?

The set opens with two leaves, numbers 1 and 2, so even a 4×4 deals both: two kinds of leaf is simply what fall looks like on the ground. The names sound like a pair made to be confused; the pictures are not. The Maple Leaf is one leaf; the Fallen Leaf is three. The maple is a single pointed leaf in deep pink-red, with a stem. The fallen leaf, singular name or not, is a little drift of three smooth, oval leaves, one red and two orange. Windows keeps them apart even on a phone-sized 9×9, light or dark: in our checks of every board size, the jagged single leaf and the scattered three never merged.

Where they do get mixed up is out loud. A child who says “the leaf goes there” hasn’t said which one, and two people sharing a board can argue past each other for a whole row before anyone notices.

A child new to sudoku can start on the 4×4 with the two leaves, the acorn and the pumpkin, then move up when the Apple and the Mushroom join at 6×6. Our Sudoku for Kids guide covers teaching the rules at home or in class, and 4x4 Sudoku and 6x6 Sudoku are those two sizes in digits, for a child ready to swap leaves for numbers.

Worked example: which leaf does column 1 need?

Here is the mix-up on a real board: a 6×6 Hard deal from this game, with 14 of its 36 squares given. The move is a hidden single in a column. Pick a picture the column hasn’t got, then check each of its empty squares for that picture in the same row or box. When only one square is left, the picture falls into place there, whatever else that square could hold.

Notice where the answer sits: R6C1, directly under the Fallen Leaf and in the same box. Take that tile for a Maple and column 1 looks finished, so you would never search it. R6C1 is not a naked single either; by its own row, column and box it could still be four different pictures. Only the column settles it. A counter of ours that runs outside the game finds a single answer, and singles are all the board needs. The Themed Sudoku page draws the same kind of move inside a box, in Christmas pictures.

Which other games share the fall pictures?

Fall lends its pictures out more than most: six of the nine turn up in other games, ten times in all. The Pumpkin, a grinning jack-o’-lantern, leads the Halloween Sudoku board in October and comes to the Thanksgiving Sudoku table in November, along with the Apple, the Corn, the Fallen Leaf and the Hot Drink. The Scarf and the Hot Drink come back for Winter Sudoku.

Matched picture for picture against the tiles of all 21 themed games. Each shared picture keeps its name in every game that deals it.

What stays home are the forest-walk tiles, the Maple Leaf, the Acorn and the Mushroom, and they make this board the outdoors version of autumn rather than the dinner or the holiday. Fall is the walk; Thanksgiving is the meal at the end of it.