I regularly play Enjoy Sudoku, at the Difficult level, and get every one. I am now learning more to move up to the Annoying level.
I recently found a website with Jigsaw Sudokus and tried one, just for fun. I got part way, but am now stuck, see http://pairofdocs.net/wp-content/uploads/2022/12/JigsawSudoku.jpg. If you would please suggest a next move, and more importantly, the strategy you used to determine that, I would appreciate your help.