Sudoku solving techniques

As in the previous post two candidate pairs in two adjacent boxes but this time with only one column or row aligning indicates that the number exisits in the comon column or row. Take a look at this page Solve Sudoku 4 and notice the candidate pairs for the number 1 in boxes 2 and 3, notice that they both have a candidate in row 3 meaning that in box 1 the number 1 can not occur in row 3.