Sudoku Help

Sudoku is a popular number placement puzzle. It consists of a 9x9 grid in which numbers are placed so that each row, column, and 3x3 region contains the numbers 1 through 9.

The Sudoku Puzzle

Figure 1: The Sudoku puzzle.
Figure 1: The Sudoku puzzle.

A Sudoku puzzle will have a number of static cells - in Figure 1, the static cells have darker backgrounds.

The puzzle is completed by positioning the available number tiles into the empty cells of the puzzle. In Figure 1, the available number tiles are in the column to the right of the puzzle's grid.

Hint Click on an empty cell to toggle a circle. Use these circles to identify the cells on which you are working.

Drag and Drop
Deltazon Sudoku consists of a drag and drop interface.

The drag and drop operation may be different on your computer, but the basic procedure is:

Solving the Sudoku Puzzle

Figure 2: Solving the Sudoku puzzle.
Figure 2: Solving the Sudoku puzzle.

Let's see how the number one is positioned in the center region of Figure 2.

The number one can only appear once within any region. Because the region is empty, the number one can appear in any cell of the center region.

The number one can only appear once in every row and column. The number ones that directly affect the center region are circled in red. The cells that are eliminated by these ones are indicated by a red X.

The only cell left in the center 3x3 region is the lower right cell, circled in green.

The Completed Sudoku Puzzle

Figure 2: The Completed Sudoku puzzle.
Figure 3: The Completed Sudoku puzzle.

The completed Sudoku puzzle contains the numbers 1 through 9 in every row, column, and 3x3 region as shown in Figure 3.