Sudoku (Part III) The last example matrix

To start from the beginning, go to: Sudoku (Part 1)

The last example of a matrix preparation is one where the letters are arranged more-or-less randomly. When doing this, I would advise stopping for a moment at a point where you have 6 filled blocks arranged, for example, like so:

At this point, you should be paranoid about checking that the blocks so far are 'true'.

The next step, is to solve the Sudoku as far as possible to see what positions are already forced (i.e. where only one letter will give true matrix), and which can only be one of two letters.

Proceeding from this point, can involve a bit of trial and error, so don't get too discouraged if you find yourself with a 'false' solution, for example, the first choice of the positions of h and i, turned out to be a mistake:

Solving the Sudoku after choosing H and I in the respective yellow shaded slots, results in the arrangement of letters shown in green capitals. You will notice in the figure above, that now there is no correct place to insert a B in the row shaded in blue. The positions of H and I were incorrect and must be reversed.

Keep repeating this process with pairs of letters until you have solved the puzzle.