Hagoromo chalk mathematics blackboard

Image by contri/Flickr (CC BY-SA 2.0)

This chalk is the stuff of legends: It glides across the board without breaking. It’s easy to erase and doesn’t get your fingers dusty. Its bright lines are legible on a blackboard. And on top of that, the chalk gives confidence and energy to whoever is using it.

Hagoromo chalk was highly coveted, so when the company announced it was going out of business, mathematicians went a little wild.

Who knew there was a “Rolls Royce” of chalk? Mathematicians, of course

While the rest of the academic world has moved from blackboards to whiteboards to smart boards, mathematicians are still scratching out their theorems with chalk. They love the stuff. It doesn’t produce fumes like whiteboard markers and you can always tell when it’s about to run out. Plus, when teaching math, powerpoint presentations are difficult and time consuming to make.

The biggest problem with using blackboards is the chalk. If it’s poor quality, the piece may break multiple times in a single lecture. Teachers might sport unknowing white smudges on their pants. Students cringe at the scratching sound produced by each character.

But Hagoromo chalk is different.

“The legend around this chalk is that it’s impossible to write a false theorem,” David Eisenbud, Director of Mathematical Sciences Research Institute, told Great Big Story.

Hagoromo chalk was only made in Japan, with special machinery. The company had repurposed flour mixing and roof tile machines to make their chalk perfect. It made the best lines and produced very little powder. Compared to other brands, Hagoromo chalk was the easiest to read on a blackboard.

For a long time, professors had to go to Japan to get it. Or, if they were lucky, they knew someone who could bring it back from a trip. Some math departments kept a stash for prestigious visitors, rarely using the prized chalk. Others stocked up when they could. Later, it was available on Amazon, making it much more accessible.

But as the popularity of Hagoromo chalk grew among U.S. mathematicians, the use of blackboards declined overall. In 2014, Hagoromo announced they were going out of business.

Hoarding and dealing in university offices

Hagoromo’s chalk sales peaked in 1990. By the time they announced the end of their business, they were selling half as many sticks as they once did. Sure, mathematicians had stuck with blackboards, but most classrooms had converted to whiteboards.

On top of the decrease in sales, Hagoromo’s president, Takayasu Watanabe, was having health issues. He couldn’t run the company anymore and since they were selling an outdated product, it wasn’t feasible to find a replacement for him. So Hagoromo announced the end of their coveted chalk.

Mathematicians did not take this announcement well. Some calculated the number of boxes they would need to last a lifetime, buying as many as it would take. The rush of orders pushed back Hagoromo’s final production by a month, but it still couldn’t make up for all the people now using markers and computers instead of chalk. It was a “chalkapocalypse,” mathematics professor Brian Conrad told Great Big Story.

But not every mathematician was quick enough to stock up on chalk. And so they began dealing. Conrad regularly sold boxes to his colleagues. Another professor, Max Lieblich, gave the first stick away for free. Of course, that single stick probably got his colleagues hooked. It’s hard to go back to cheap Crayola after trying the Rolls Royce of chalk.

“I assume the special ingredient was angel tears,” Lieblich told Great Big Story.

But just as the math world descended into shady chalk deals, the story took a twist.

Watanabe found a South Korean company to buy two of his chalk machines. He personally went there and taught them his chalk recipe and how to make the sticks. Presumably, he told them whether the secret ingredient was angel tears or not.

And just like that, the chalkapocalypse was avoided.