Williams College math Professor Satyan Devadoss wrote in 2010 ("Dream Chalk"):

... 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. It is called the Hagoromo Fulltouch Chalk.

For those lucky few who have used it, it can truly be called the Michael Jordan of chalk, the Rolls Royce of chalk. It is made in Japan, and is a bit larger than the classical American chalk. Moreover, it comes with a wonderful coating which protects the user from chalky hands. Once you've used it, there is no going back.

Devadoss also noted that better chalk can actually help one think better:

... Let's not be dualistic like the ancient Greeks, saying our minds and our bodies are distinct. We are a whole being, where the tools we use to write with impact what we write about. (The same can be said of ballpoint versus fountain pens, but that's another story.)

A flurry of essays in June 2015 quoted or echoed Prof Devadoss, when the company in Japan that made the chalk went out of business. (Not much commentary since then. Has intellectual progress slowed?)

(cf "Why Mathematicians Are Hoarding This Special Type of Japanese Chalk" by Sarah Zhang, "What's So Special about This Japanese Chalk" by Elizabeth Armstrong Moore, "A Teary Goodbye to Hagoromo" by Jeremy Kun, ...) - ^z - 2019-03-25