Place a number into each empty cell so that each cell has exactly one number and cells that contain the same number do not touch each other, not even diagonally. Each outlined area must contain the numbers from 1 to N (where N is the size of the outlined area in cells) such that consecutive numbers within an outlined area are orthogonally adjacent. (In other words, for each region it must be possible to draw a path that starts at 1 and ends at N, going through each other cell exactly once and in numerically increasing order.)
(Rules and example from PGP IB)
- Meandering Words: Invented by Daisuke Takei (Japan) for 2007 Japanese National Final. (hence making it the precursor to numbers version) Instead of numbers, each region must contain a word from the given list. They are placed such that consecutive letters in the word are touching each other by a side.
History of the puzzle
Invented by Daisuke Takei (Japan) in 2014. First appeared on Japanese round of 2014 Puzzle Grand Prix as "Count Number". The name Meandering Number was first given in Toketa volume 2 (2014). Refer to Toketa for more detailed history of this puzzle.