(upbeat music)
- The legend around this
chalk is that it's impossible
to write a false theorem.
- I assume the special
ingredient was angel tears.
- Mathematicians from all
of the top schools very
frequently use it.
- It's a cult favorite.
- As soon as I use it I was a convert.
- The chalk is one of
the best kept secrets in
the math world.
- It's the Rolls Royce of chalk.
(gentle music)
(chalk scratching)
- Hagoromo is a brand of Japanese chalk.
The way it flows on a board
is a bit hard to describe
in words.
- It's really hard to get.
You can only get it from
Japan, you need a Japanese
person to bring it back for you.
- I discovered it when I went to visit the
University of Tokyo and
one of the professors there
said to me, you know, we have better chalk
than you do in the States
and I said, oh go on,
chalk is chalk.
And so I tried it out, and
I was surprised to find
that he was right.
- I tried it, and I
thought it was phenomenal.
It's the densest, it erases the cleanest,
it leaves the nicest line.
- If you use bad chalk
often you have to press
really hard for anyone to
see what you're writing
so using Hagoromo on a good
board, it doesn't really
feel like you're working hard to write.
- When I'm teaching I
get a feeling of energy,
confidence, and the
chalk absolutely helps.
(chalk clacking)
- Slowly the math world
has become aware of this,
and it became a bit of
a fad in some circles.
(upbeat music)
- It was like maybe four
years ago the word came out
that the company was
going out of business.
I sort of jokingly referred
to it as a chalk apocalypse.
So I immediately started
hoarding up as much as I could.
- I ordered three boxes
of Hagoromo and kept it in
my office and used it very sparingly.
- I should've bought more but
I have friends that bought
boxes and boxes and boxes of the stuff.
They might very well be set
for the rest of their career.
- We've got like 1,500 sticks.
That's a lot of days, four sticks a day.
I think I'm gonna make it.
- I have probably a 10-year
supply still at home.
- I calculated how many boxes
would I need to last for
10 or 15 years.
I didn't wanna become a chalk
dealer, but I did like the
idea that I could be
the first stick is free
chalk dealer on the
block in my department.
- I was probably selling
it regularly to maybe
eight to 10 colleagues.
I would reach into my
cupboard in my office
and pull out another
box and we'd do the deal
in my office.
Yeah, we all had a chalk fix.
And we still do.
(gentle music)
- The original Hagoromo
chalk is slowly disappearing.
A few years ago, a Korean
company bought their formulas
and did the best job of
faithfully reproducing it
in Korea.
- It was mixed emotions.
I was happy to know that
it would still be made.
But I was a little disappointed
that I was less clever
than I thought I was.
(gentle music)
- In many ways mathematics
is like craftsmanship,
in some ways it's like artistry;
in some ways it's like science.
But there's a real high
craft side to getting
a beautiful lecture on a blackboard.
Mathematicians admire this in each other
and like to use the best tools for it.
- There's incredible value
to this but the value
is in using it up, not hoarding it.
(gentle music)
