Why Mathematicians Are Hoarding This Special Type of Japanese Chalk

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.

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