hobby and craft

Mathematicians No Longer Have to Hoard This Japanese Chalk

Hagoromo can be bought by the box on Amazon now. Photo: Bobby Doherty

Two weeks ago, online documentary site Great Big Story premiered a mini-film on Hagoromo Fulltouch Chalk, the legendary Japanese chalk with a cult following among mathematicians (as one of them says, “one of the best-kept secrets of the math world.”) We first wrote about Hagoromo chalk in the magazine four years ago as one of the “115 Ways to Scream ‘Status,” and at the time, professors were hoarding the stuff, as rumors swirled that Hagoromo was going out of business. Fortunately, that didn’t happen. “Honestly, the video made it sound very hard to buy, and that was true some years ago,” says Wei Ho, an associate professor in mathematics at the University of Michigan, who was featured in the film. “At this point you can just buy it on Amazon, so I just bought a few boxes on Amazon maybe five years ago, and I haven’t even gone through the whole stash.”

Ho loves the chalk for its buttery smoothness. “It’s a lot easier to write with it, so you don’t have to think about writing,” she says. “In fact, I gave a lecture last week, and at first I was using this other chalk, and I felt like I was using 25 percent of my brain thinking about how to press on the board with this giant piece of chalk. At some point, someone in the audience was like, ‘Uh, your chalk isn’t working very well,’ and I was like, ‘Oh! There’s a little piece of Hagoromo, a little stub of Hagoromo on the board, I’ll use this instead’ and it made me feel like the talk went a lot smoother because I didn’t have to think about how I was actually writing on the board.”

Hagoromo is smoother than other chalks because each stick has a waxy coating — it doesn’t stain your hands when you write. “You still get chalk dust around, but it’s less than with other brands of chalk,” says Ho. “Normally I’m just covered in chalk, regardless, after a lecture, but this minimizes it a bit.” She compares the ease of using Hagoromo to another instrument. “If you write with a nice gel pen, it feels like it just flows across the page — it’s the same idea,” Ho says. “For me, it’s exactly the same feeling as writing with a really nice pen, versus a normal ballpoint pen, or something.” (We can confirm: there is currently a stick of Hagoromo chalk in one of the New York Magazine conference rooms, and it does feel good to write with.)

“I was very surprised how popular it became,” Ho says of the video about the chalk. “When I was asked to do it, I did not think anyone would see it besides other mathematicians … I’ve gotten emails and texts from all sorts of people. Several people have told me that they never use chalk, they don’t have a chalkboard, but they really want to buy it.”

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Mathematicians No Longer Have to Hoard This Japanese Chalk