Throwback Thursday Solution

Sudoku has a vast history! 

Conceived in Switzerland by Leonhard Euler (1782), The puzzle consisted of only letters and required every letter appear once in each row and column.

Modernized to its current version in America by Howard Garnes (1979) , Garnes introduced the current version of the puzzle with nine 3x3 sections in American Dell Magazine.

Popularized in Japan in Monthly Nikolist (1984).  Since crossword puzzles are difficult to make in Japanese, Sudoku presented an easily accessible puzzle for papers and magazines.  This is also where the puzzle obtained its current name.