[This is a repost from our archives with new notes at the top: Looking back at past work can show some of the interesting changes with time. For instance, our original GMPuzzles posts like this one from our first week of puzzles used more of a “conversation title/theme” which slowly became just short phrases — or no theme when it was just logical over the years. (Other very obvious updates will include removing the solving arrows, changing solving time standards, and adding in difficulty ratings — we have not tried to make any of those changes this week and have the most stripped down versions of the post here with the goal you might go back to the original.)
There is something refreshing to find after reading that “an exclusively logical theme will be revealed during the solve”. I just went through the puzzle again and found it, but then I have the unfair advantage of better knowing how to read my younger mind. I wonder when I’ll run into a puzzle where past me outsmarts current me.]

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Besides symmetry, an exclusively logical theme that will be revealed during the solve.

Rules: Standard Sudoku rules.

Estimated Difficulty*: 3.5 stars

Time Standards (highlight to view): Grandmaster = 5:00, Master = 7:30, Expert = 15:00

Solution: PDF and solving video.

Note: Follow this link for other classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More classic Sudoku puzzles can be found in our e-store, including in The Art of Sudoku, The Art of Sudoku 2 and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.