This year, we have started to have some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This second Sunday Stumper is a challenging Sudoku variation with a special theme for Pi Day, whether you like Pi or are in the Anti-Pi = Tau camp.
or solve online (using our beta test of Penpa-Edit tools)
Author/Opus: This is the 320th puzzle from our managing editor Serkan Yürekli.
Rules: Standard Sudoku rules. Also, no two of 3, 1, and 4 can appear in adjacent cells. Some cages are marked by dashed lines; the sum of the digits in each cage must equal the value given in the upper-left corner of that cage (digits cannot repeat inside a cage). Some arrows given outside the grid indicate the sum of the digits along that diagonal path (digits can repeat on a diagonal). The value of any ungiven sum in either a cage or an arrow must not be a number composed solely of the digits 3, 1, and 4 (like 4, 11, 14, 31).
Difficulty: 5 stars
Time Standards (highlight to view): Grandmaster = 28:00, Master = 1:00:00, Expert = 2:00:00
Solution: PDF; a solution video is also available here from Dr. Sudoku and another video here from Cracking the Cryptic.
Note: Follow this link for other variations on Sudoku.