This puzzle was first published in New York in the late 1970s by puzzle publisher Dell Magazines, under the title 'Number Place'.
In 1984 it was introduced in Japan by Nikoli as "Sūji wa dokushin ni kagiru" (got abbreviated to Sudoku). This tranlates to 'the numbers must be single'.
After some modifications the puzzle game has taken the world by storm in recent years.
Fill in the 9x9 grid and ensure every column, row and box contains numbers from 1 to 9.
Use the Hint by first selecting a square you need help on.
Strictly Sudoku is an online puzzle game and has been played 73098 times on Bubblebox.com.