This spring, an 80-year-old Japanese chalk company went out of business. Nobody, perhaps, was as sad to see the company go as mathematicians who had become obsessed with Hagoromo Fulltouch Chalk, the so-called “Rolls Royce of chalk.”


With whiteboards and now computers taking over classrooms, the company’s demise seemed to mark the end of an era.

Being neither a mathematician nor a chalk artist, I heard about Hagoromo through my friend Dan, a mathematician finishing up his Ph.D. at Stanford. He recently appeared on a Japanese TV special about the demise of Hagoromo Bungu Co., where a TV crew came out to Stanford to interview mathematicians about the legendary chalk. One professor described hoarding enough of the stuff to keep him in chalk for the next 15 years. Dan is in the special too, calling the end of Hagoromo “a tragedy for mathematics.”


Okay, he was obviously joking. But it is true that mathematicians are fanatics for this obscure Japanese chalk. Here you can see a long discussion online where mathematicians are hunting for Hagoromo chalk suppliers in the U.S. Satyan Devadoss, a Williams College math professor, even wrote a blog post calling it “dream chalk.” He explained:

There have been rumors about a dream chalk, a chalk so powerful that mathematics practically writes itself; a chalk so amazing that no incorrect proof can be written using this chalk. I can finally say, after months of pursuit, that such a chalk indeed exists.

How could mere chalk inspire such hyperbole?

I called up Brian Conrad, the Stanford math professor who socked away 15 years worth of Hagoromo chalk. It turns out he’s the biggest customer of Ten By Ten, a small Oakland-based importer of Hagoromo chalk.


I visited Ten By Ten to get some of the chalk for myself, and discovered that the company is just one woman, a filmmaker who sells chalk out of her Oakland loft as a side business. She got into it when she met a Berkeley math professor while editing a film. He asked her about getting ahold of his beloved Japanese chalk, on one of her trips back home to Japan. Today, most of her clients are mathematicians.

So what’s so great about Hagoromo chalk? I tried doing a little math with it on some chalkboards at UC Berkeley. The first thing you notice is a shiny, clear coating on the outside — it feels like a thin layer of enamel. That sounds like a minor design element, but it cuts down on the biggest annoyance with chalk: dusty fingers. The chalk is also a tad thicker and sturdier than your typical American sticks. But I’m no chalk connoisseur, and I’ll admit any subtler differences eluded me. “It’s hard to articulate but when I’m using it, I can feel it’s nicer,” said Conrad. “It both flows nicely and it lasts much longer, too.”


The bigger question, though, is why mathematicians are still clinging to chalk, period. In the 21st century, chalk is still one of the primary tools of mathematicians. “Because we’re crotchety old people,” joked Conrad. Powerpoint slides, he noted, don’t work for writing out a problem step by step. Plus, technology has that annoying tendency of becoming glitchy at the most inconvenient times.


What really surprised me, though, were all the reasons he had for finding chalkboards superior to whiteboards. “Maintaining a clean whiteboard is much more of a pain,” he said. There’s the cleaning fluid, which costs money, and the chemicals can cause health problems. Also, there’s no way to tell when a marker is running low, which is logistically, he explained, even more annoying than you think. “Because you can never tell when any of these markers are running out, people use them at random, and they all start running out at the same time during a talk. It’s a real nuisance,” he said. “I just find the logistics of carrying around a couple pieces of chalk easier than dealing with markers.”

Conrad is pretty self-aware that his preference for chalkboards over whiteboards might just be a habit—and mathematicians as a whole have just been holding out longer than those other fields. A younger generation of mathematicians, raised on markers and whiteboards, might never yearn for the chalk.


When the elderly owner of Hagoromo Bungu gave up his company in March, the technology for making Hagoromo chalk was transferred to Uma-jirushi, a big office supply corporation. Uma-jirushi now makes DC Chalk Deluxe, which it bills as a collaboration with Hagoromo. A company rep said the manufacturing process is slightly different, but assured me that customers should expect the same high quality. Still, the rep added, Uma-jirushi’s chalk production will amount to just half of Hagoromo’s. These days, they’re primarily a whiteboard company.




This isn’t just a story about a dead chalk company—it’s the story of a dead medium, the chalkboard, now being superseded by whiteboards and tablets. But it’s not hard to see chalk having old-fashioned appeal, much like vinyl records and mason jars. For now, the chalk is still available on Amazon. Get it while it lasts.