or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)
Theme: Four Nonets
Rules: Standard Outside Sudoku rules.
Answer String: Enter the 5th row from left to right, followed by a comma, followed by the 5th column from top to bottom.
Time Standard: Outside Sudoku Grandmaster = 2:15, Master = 3:00, Expert = 6:00