Forcing chain can actually help you determine exactly what number a certain cell must hold. Unfortunately, the technique is not the easiest to utilize. Look at the example below. Let us assume that the candidates in the red cells are the sole candidates for those cells.

Now that you know the Sudoku game rules, let’s look at how these rules determine how you play Sudoku. In addition, the grid contains grey arrows. The number to be placed in the circled cell at the start of each arrow is the sum of the digits that fall along the path of the arrow. In addition to the arrows, it will immediately be noticed there are many less givens than with a standard sudoku puzzle. But this is compensated by the fact that the arrows provide additional information - if you know how to access that information!

Interesting Facts about Sudoku

This method won't help you pencil in any new numbers, but it will help you nail a number down within a specific row or column. The example shows that the number 7 can only be inserted in the red cells of the middle row. Thus you can remove 7 as a possible candidate from the rest of the row.

This method can work when you look at cells comprising a rectangle, such as the cells marked in red. In this example, let's say that the red and blue cells all have the number 5 as candidate numbers. Now, imagine if the red cells are the only cells in column 2 and 8 in which you can put 5. When utilizing these techniques, the way the pros prefer to do it, is to start with the basic ones. Use the first few techniques to insert as many numbers as you can. Then, when you can add no more numbers to the board using the basic techniques, try the more advanced ones. Do one at a time until you can plot one more number into a cell. Then, start with the basic techniques again, and repeat the process. You should be able to solve almost any Sudoku puzzle using these techniques. In addition to the standard Sudoku rules of every row, column, and 3×3 region containing the numbers 1 to 9 once and only once each, Arrow Sudoku only has one additional rule.

If you would like to comment on this post, please enter your comments below; all fields are mandatory. Posts are moderated before display. Your solving tips are good, although I'd worked those out for myself, and still haven't finished one!