Hitori rule
Eliminate numbers until there are no duplicates in any row or column.
Eliminate numbers by marking them in Black.
Black squares can't touch horizontally or vertically (diagonally is ok).
Any White square can be reached from every other (i.e. they are connected).
Hitori (from Japanese "Hitori ni shite kure"; literally "let me alone") is a type of logic puzzle.
Hitori is played on a grid of squares. At the beginning, each cell contains a number. The goal is to paint out some cells so that there are no duplicate numbers in any row or column, similar to the solved state of a Sudoku puzzle (except with black squares added to the grid).
Orthogonal connections are important as well; painted-out (black) cells cannot be connected orthogonally, and the other cells must be connected orthogonally in a single group (i.e. no two black squares can be adjacent to each other, and all un-painted squares must be connected, horizontally or vertically, to create a single shape).