Typically 81-digit diversion

• Number-logic puzzle
• Number placement puzzle with a 9 x 9 grid
• Puzzling form on the upturn, United knocked us out
• Digital challenge
• Craze of 2005-06
• Upstanding partners in supposed special relationship about to complete puzzle
• Crossword alternative
• 9 x 9, 1-9 puzzle
• Popular logic puzzle

Wiktionary Word definitions in Wiktionary
n. (context games puzzles English) A type of puzzle whose completion requires each of typically nine rows and columns and each of as many usually square subregions to contain, without duplication, 1 up to 9 or the grid dimension.