Number puzzles first appeared in newspapers in the late 19th century, when French puzzle setters began experimenting with removing numbers from magic squares. Le Sicle, a Paris-based daily, published a partially completed 99 magic square with 33 sub-squares in 1892. It was not a Sudoku because it contained double-digit numbers and required arithmetic rather than logic to solve, but it shared key characteristics: each row, column and sub-square added up to the same number.
Within three years Le Sicle's rival, La France, refined the puzzle so that it was almost a modern Sudoku. It simplified the 99 magic square puzzle so that each row and column contained only the numbers 19, but did not mark the sub-squares. Although they are unmarked, each 33 sub-square does indeed comprise the numbers 19. However, the puzzle cannot be considered the first Sudoku because, under modern rules, it has two solutions. The puzzle setter ensured a unique solution by requiring 19 to appear in both diagona