Idoku trick

I am no expert on sudoku but a useful trick with the i sudoku is shown here.

Whatever number is at the z location in the bottom square will be the same as the number labelled z in the centre square and vice versa.

 With the x/y numbers, whichever numbers are in those positions in the lower square will be replicated in the top square. This trick cuts both ways. If a number cannot be at one z location it cannot be at the other z location.

Likewise, if a number cannot be at either of the x/y locations in the top square it cannot be at those locations in the bottom square.

Look at the idoku. The central line of nine squares contains the same numbers as the i shape. The rule of idoku is that the numbers one to nine must be in the letter i on the sudoku

The number at z in the bottom square precludes any of the small orange squares in that larger square from being that number. It also precludes three of the orange squares in the central square and the solitary orange dot in the top square.

I hope that is clear.