Hi! A happy Easter weekend to those who celebrate.

Today, I’m going to talk a bit about sudoku. If you don’t know what that is, click that link first. You’re given a 9×9 grid with nine 3×3 subregions contained therein; in any given row, column, or region, the numerals 1 through 9 appear exactly once. Typically, you’re also given a handful of boxes already filled in with the correct answer, and from there, you need to figure out what goes in the empty boxes. Those are the basic rules and despite how simple, individual puzzles can be very hard. (If you want to try an easy one, though, click here.)

For many, that’s where the conversation around sudoku begins and ends. But there’s a small community of sudoku solvers that add all sorts of variant rules — variants that typically make the puzzle harder.

About a year ago, I shared a video using one of those variant puzzle sets. The board itself has only two boxes pre-filled in and a bunch of rules that seem inadequate to allow the solver to reach a solution. Here’s how I described it then:

The Miracle Sudoku” (YouTube, 26 minutes, May 2020). Okay, so let’s start by saying that this sounds super-boring, I know. It’s literally a 26-minute of some guy solving a Sudoku puzzle. If you don’t know what Sudoku is, you may want to read about that for a moment before you start. Otherwise, you’re probably thinking “why would I possibly want to watch this video.” And I admit, the two minutes aren’t promising, as the host just talks to his fans and gives some background. You can probably skip that part but really, it’s two minutes of your life, I’d just humor the guy.

At about the two-minute mark, he begins explaining the special rules. That takes another 90 seconds or so and you shouldn’t skip it, or the rest won’t make sense. After that, it begins, and before you know it — it’s magic. There’s no other word for it. If you don’t want to take my word for it, it found this via Jason Kottke’s excellent, long-running blog, and he correctly describes it as “ludicrously entertaining.”

Since then, I’ve discovered — and attempted — a dozen other Suduko boards shared on that YouTube channel. And the “miracle” one is one of the easier, more straightforward ones. Here’s what a somewhat recent one looks like, discussed and solved at this video.

The rules, per the video’s description: “Normal sudoku rules apply. In cages, digits must sum to the small clue in the top left corner of the cage. Digits cannot repeat within a cage. Digits along an arrow path must sum to the digit in that arrow’s circle. Digits can repeat along arrows (if allowed by other constraints).”

No boxes are filled in but I promise, it’s solvable — the arrows and cages (and their corresponding rules) make it so. I wasn’t able to do it myself, at least not without getting stuck a few times, but I watched the video to get un-stuck. If you want to try it yourself, you can here, although I’ll warn you — it took the expert sudoku puzzle solver more than half an hour to do so in the YouTube video. And that’s actually one of his quicker attempts.

Oh, and one other warning: Sudoku solving is its own rabbit hole.

In any event, watching someone try to figure this thing out is, surprisingly, very interesting and compelling television. No, it’ll never replace real TV, but you may find it a lot more enjoyable than you’d think — and you can very easily (although likely unsuccessfully) play along.

The Now I Know Week in Review

Monday: Nothing to Carp About: It’s not really a Passover story, but it’s close.

Tuesday: The Loophole With Two Wheels: Why Syrians rented bicycles in Russia.

WednesdayHow to Rent a Friend: A unique service offered in Japan.

Thursday: Dormant and Tired: My favorite April Fools joke.

And some other things you should check out:

Some long reads for the weekend.

1) “The Mister Rogers No One Saw” (The New York Times Magazine, November 2019). If I find a long read about Mr. Rogers, I’ll probably be sharing it. The subhead: “Fred Rogers wasn’t just a brilliant educator and a profoundly moral person. He was an uncompromising artist.”

2) “Getting Plowed” (Maisonneuve, April 2012). The subhead: “In this exclusive investigative report from Montreal, Maisonneuve exposes the bid-rigging, violence and sabotage at the heart of an unlikely racket: snow removal.” Yes, snow removal. (And no, Homer Simpson is not from Montreal.)

3) “How Not to Deal With Murder in Space” (Slate, 6 minutes, July 2020). The first paragraph is a doozy: “Mario Escamilla was furious. A colleague of his, nicknamed Porky, had just stolen his jug of raisin wine. So the 33-year-old Escamilla grabbed a rifle and set out to reclaim it. He had no idea he was about to get tangled up in one of the knottiest homicides in history—a killing that also raises serious questions about how humankind should handle the first, inevitable murder in outer space.”

And a bonus: “They Just Wanted Their Couches. An Accidental Reply-All Email Storm Followed.” (Wall Stree Journal, 5 minutes, March 2021). This is behind a paywall or it’d not be a “bonus” item. The short version: A furniture company had some delays in shipping etc., so they sent a mass email to their affected customers. But they didn’t hide the recipient list and people started replying back. And then, nice things happened. (Yes, nice things!)

Have a great weekend and a happy Easter to those celebrating!

Dan