Place the numbers I - IX in the grid so that every row, every column, and each of the IX III by III squares contains only one occurrence of all the numbers from I to IX. This version, is intended to exercise the left brain more than the right, unlike the puzzles below, which also involve the visual right brain.
You should be able to solve these puzzles without writing anything down, and they all have only one solution. If you feel you can't go, you can click the 'give me a hint' button, and any errors you have made will be highlighted in red, or if you've made no mistakes, a green square will show where you can go next. If you try to place a number where it already exists on that row, column, or small square, both occurrences will be highlighted in red.