I am trying to pick up advanced sudoku techniques by practicing with “difficult” puzzles as suggested by my sudoku app.
In this puzzle, I am stuck in the position as shown below. I think I can make use of forcing chains to break the puzzle, but I am unable to pinpoint the exact cell I should look at.
Is it possible to find a forcing chain in this puzzle which greatly simplifies the position? I neither wish to bifurcate, nor resort to a computer solver.