Sudoku

Brain teaser with a twist

This is the classic version of the well-known number placement puzzle and a real brain teaser, perfect for enjoying some quiet time by yourself and sharpening your mind. Start at the entry level and work your way up to become a sudoku master or even zen master and play against the clock. 
Played in a 9x9 grid, enter various numerals between 1 and 9 in the vacant spaces. Now, the tricky part is that each row, column and 3x3 box must contain only one instance of each numeral. Need a little help? Pencil in numbers to jog your memory, or click the lightbulb for some clues. Join the craze and train your brain!