Dear solvers,

I hope you all enjoyed the “Best of 2020”. The collected PDFs are in all the web posts and also on our all weekly PDFs page.

Our “Best of …” selection process tried to be as consistent as possible with prior years, but some technical issues with the solving/fave widget meant we did add in web comments and tester feedback as additional signal for the best puzzles. If you think we missed a particularly awesome puzzle, please tell us (and in 2021 keep commenting on the posts when you like something as that is the most direct way for authors to see your feedback).

One small update on the solving widget: there are still users with login issues and the necessary fix requires a larger lift-over of the tool and database to our servers; we’ve contracted for this project so hope it returns to its old form in the next couple months.

One big update for 2021 is that we are going to include a digital solving option with automated solution checking for all puzzles.* We have set up Penpa-Edit on our site, and will be using it in a kind of “beta” mode as we find the best ways to present a variety of puzzles (with good documentation/instructions) including making some style changes over the coming months to integrate the current version more with the site. At the start, a lot of the help may be missing so if you aren’t already an experienced Penpa user, please look for some of our first solving videos to help a bit.

One last update for now is that in 2021 we will have a few “Sunday Stumpers” that are very, very hard puzzles. Seeing how difficult puzzles can seem fair to post if there are solving walkthroughs eventually connected to show the logical route, we will try to post a Sunday Stumper once a month including next Sunday at the end of our “Welcome to 2021” week. New puzzles, including the first with penpa-edit, will start tomorrow.

Best wishes for a great 2021,
Thomas (aka. Dr. Sudoku)

(*One impressive thing about Penpa-Edit as it has grown is that we can cover 99+% of the puzzles we’ve posted in the past — there is only one puzzle in our initial weeks of 2021 where a slight modification will be required to present the puzzle in a solvable form.)