1) Logic puzzle 
Kuromasu (Japanese:黒どこ kurodoko) is a binary-determination logic puzzle published by Nikoli. As of 2005, one book consisting entirely of Kuromasu puzzles has been published by Nikoli. ==Rules== Kuromasu is played on a rectangular grid. Some of these cells have numbers in them. Each cell may be either black or white. The object is to determin...