Sudoku

Rules
. Use the numbers from 1 to 6.
. Every row must have all the numbers from 1 to 6
. Every column must have all the numbers from 1 to 6
. Every sub-rectangle must have all the numbers from 1 to 6
(A sub-rectangle is the 2 X 3 rectangle; the 6 X 6 square is broken up into 6 such sub-rectangles.)
Use the numbers already filled in as hints to complete the grid. Send in your filled-in grid to us at the JM address given elsewhere in the magazine and win a "sur-prize"! Don't forget to write in your full name and address.
Each Sudoku puzzle has a unique solution. If you find the "EASY" Sudoku a walk-over, try the "MEDIUM" challenge!