Hi!

A few times in the past couple of years, I’ve shared variant sudoku boards with you, suggesting you give it a try. I’m going to do the same in a bit, but first, a quick explanation. Sudoku, if you’re not familiar with it, is a solo game — you’re provided a 9×9 grid with nine 3×3 boix inside, and you have to place the numerals 1 through 9 exactly once in each row, grid, and 3×3 box. Typical sudoku boards give you a handful of numbers already placed. They’re fun, but kind of tedious after a while.

Variant sudoku boards are a lot more fun — because they take away most of the given digits and instead, give you some weird rules. I discovered these a few years ago; a puzzle solver named Simon Anthony took to YouTube to solve a puzzle provided to him by his friend and YouTube co-host, Mark Goodliffe. First, his given a totally blank grid and two additional rules: “Any two cells separated by a knight’s move or a king’s move (in chess) cannot contain the same digit. Any two orthogonally adjacent cell [that is, they share an edge] cannot contain consecutive digits.” After reading the rules, he clicks to see the reveal of numbers already provided, expecting a bunch — and he sees that the board was totally blank except for one 1 and one 2 placed in the grid.

His immediate reaction was “Right. [Mark] has got to be joking. There’s no way that this [is solvable] by a human being.”

But Simon gives it a go anyway, and 20 minutes later, he’s solved the puzzle.

I’ve shared this before, so if that feels familiar, that may be why. In any event, I’m hooked on these puzzles, and apparently, I’m not the only Now I Know reader (am I a “reader”?) who is. James Sinclair learned about the YouTube channel above from Now I Know and has created a newsletter of sudoku variants called “Artisanal Sukoku,” which you can find and subscribe to at that link. I’ve been a subscriber for a while now and a few weeks ago a tackled one of his more difficult puzzles — per his own rating system at least — and solved it! I thought the solution was really elegant given how clean the puzzle was in particular, and asked him if I could share it with you all at a future date. He said yes, so I’m sharing…

but there’s a catch.

The puzzle and rules are below. The catch is after. (You’ll have to keep reading, hah!)

The rules:

* Fill each row, column, and 3×3 box with the digits 1-9 once each.

* The sum of the digits inside each cage is equal to the small number in the top left corner (if given). Digits cannot repeat within a cage.

That’s it! The cages are shaded to make them easier to see; the colors don’t mean anything. You’ll note that the four-square cage shaded in blue doesn’t have a small number in it; that’s not a mistake. Anyway, if you want to give the puzzle a try, click here. I’ll warn you, though — it’s hard.

I know it’s hard because even though I solved it a few weeks ago, I just gave it another try and…  I’m stuck! If you don’t want to solve it but do want to help me get unstuck, here’s a screenshot of where I was when I basically gave up. Don’t click that link if you want to try it yourself, though!

I’m pretty amused by my failure here — I definitely solved it a few weeks ago, and I have no idea what I”m doing wrong now. I guess I used to be smarter?

## A Quick PSA

In most of the United States, Daylight Saving Time ends Saturday night (well, very early Sunday morning), so don’t forget to change your clocks! Yes, yes, most will change on their own, but I’m trying to be helpful here.

Also, if you’re wondering why we still have DST and/or are looking for some good trivia about clocks changing, I wrote something last year that is perfect for you!

## The Now I Know Week in Review

Monday: Trick-or-Treating… But on Thanksgiving?: I say we give and receive candy on both holidays. In fact, let’s do it monthly! Wouldn’t that be great?

Tuesday: Why You Shouldn’t Piss Off The Architect: Spite, it Italy, via art.

Wednesday: The Original Chicken Dance?: Spite, it Italy, via art.  But different than the one above.

Thursday: That Font That Toppled a Government: A lot of you made a “San Sharif” joke. Well done!

## And some other things you should check out:

Some long reads for the weekend.

1) “The Marree Man: an outback enigma” (ABC Australia, 10 minutes, July 2019). The picture above is the Marree Man. It’s a 4.2 km tall (2.6 miles) drawing in the Australian outback. It was created in the late 1990s. And as the story shares, we’re not really sure who made it. Thanks to reader Bryan P. for flagging this one for me.

2) “She Spent a Decade Writing Fake Russian History. Wikipedia Just Noticed” (Sixth Tone, 6 minutes, June 2022). The subhead: “A Chinese woman created over 200 fictional articles on Chinese Wikipedia, writing millions of words of imagined history that went unnoticed for more than 10 years.” Thanks to reader Robert C. for this one!

3) “The Secret to This Taiwanese Town’s Tofu Is a Mud Volcano” (Atlas Obscura, 7 minutes, April 2021). Thanks to reader John G. for sharing this great article with an even better title.

Have a great weekend!

Dan