
Mathematicians are hoarding a type of Japanese chalk (2015) - florian_s
https://gizmodo.com/why-mathematicians-are-hoarding-this-special-type-of-ja-1711008881
======
Syzygies
My Hagoromo chalk and eraser notes:

[https://www.math.columbia.edu/~bayer/LinearAlgebra/Video/Cha...](https://www.math.columbia.edu/~bayer/LinearAlgebra/Video/Chalk.php)

CNN is doing a short web video on this chalk, and I was interviewed last week.
They particularly liked my custom attache case for carrying all my colors to
teach. When I drew diagrams revealing Catalan number correspondences, they
were quite worried that these pictures "weren't math" and I might be
hoodwinking them.

The "eraser" is a side category that doesn't get enough attention. At MSRI one
uses auto detailing "applicator sponges" which choke pretty quickly with chalk
dust, but are nevertheless superior to traditional erasers. Far better is a
supply of auto detailing towels; here, Korean microfiber is unrivaled. For
classes late in the day, I use one wet to wash the boards, then a dry one to
erase as I work. When I run out I do laundry; these towels are indestructible.

So why use the sponges in a public setting? We're learning that animals in
many particular tasks exceed human intelligence; it's a matter of each
creature's focus of attention. Mathematicians like to believe that we're
smarter than average, but we're actually just very focused. That can make us
pretty dumb away from our focus of attention. A nervous mathematician giving a
public lecture is unlikely to recognize what a towel is for, but a sponge has
the right form factor. It's like making your modern heating in a bed and
breakfast look like fireplace logs, to not confuse the customers.

~~~
thanatropism
> Mathematicians like to believe that we're smarter than average, but we're
> actually just very focused.

Serious question: does this spell doom for people with ADHD?

~~~
trentmb
> Serious question: does this spell doom for people with ADHD?

Caveat: undergrad in math, working on a part time coursework masters (I'm
hoping to talk someone into being my advisor for a part time thesis)

No more so than any other academic subject.

If anything, I've found math _more_ friendly to my ADHD than philosophy,
literature, etc.

~~~
thanatropism
I successfully completed an Applied Math masters and defended a dissertation
on symplectic integration. But that didn’t quite give me the superpowers my
professors had.

------
wirrbel
I studied physics and this at a time when faculty gradually changed from
blackboard-based lectures to powerpoint. The blackboard-based lectures were
far superior to any other way of lecturing (in my view).

Main benefit was in the speed of presentation. Writing on a blackboard takes
some time, the lecturer is slow enough in presenting that you can really
follow along, while not "standing still". What a contrast to powerpoint
presentations where the lecturer paused for a minute or two to let students
read the equations. Either time was not enough, or you'd start to get bored.

Until I graduated at the end of my 5 year program, I tutored freshmen
students. Towards the end of my time at uni, they almost exclusively had
lectures with powerpoints. I sat in one of the into lectures and what had been
a good introductory course to classical mechanics had turned into a mind-
numbing powerpoint karaoke show.

~~~
conjectures
I find another benefit of blackboard presentation is the _order_ of
information. The lecturer can build something up rather than simply showing
the finished article and saying voila.

~~~
leereeves
But slides have one big advantage: they can be posted online for later review
so students can follow the lecture instead of taking notes.

~~~
spicytunacone
I had a math instructor record his blackboard lectures and posted them online
later that day. Just another consideration.

~~~
moftz
If the professor just recorded the lecture, I'd imagine most students would
never go to class again.

~~~
max76
If no one goes to the physical classroom why not sell the same recorded
lecture to a thousand people online instead of the 100 that fit into a
classroom?

~~~
moftz
I had a world history/geography/current events kind of class in college that
had an in-person lecture and was also livestreamed and recorded. Lecture hall
fit about 1800 people but he also had an unlimited class size "online" section
you could sign up for if you didn't get in-person section during early course
request. You never actually had to go to class. The professor had to get his
own system for taking quizes and handing in assignments since the online
learning management system the school used would choke with that many students
at once trying to submit things.

Content aside, it was a very interestingly run course. Assignments were at
your own pace, you had a large list of the kinds of projects you could turn in
for credit. There were quizzes, exams, essay topics, interview topics, and an
option for independent projects to get credit. Each kind of project had it's
own maximum point value it would be graded out of and the final grade was
totally based on how many points your actually earned, not out of how many.
Even if you did a shit job on every assignment, as long as you did enough of
them, you could get an A. It was a nice way to boost the GPA from just sheer
effort rather than actual achievement.

------
LeifCarrotson
Hands-down, the best presentation and note-taking math class I recall in
college (discrete mathematics, a graph theory course, heavy on drawings) was
run through a Wacom pen display on the lectern, linked to a projector. The
professor could accurately and cleanly draw the required notation with his
hand flat. Why erase when space is infinite, just scroll and/or zoom in the
desired direction. A full color spectrum was available. If something needed a
chart or other graphic to better explain, that was a swipe away. And the
output of the lecture was always available after class, so you could take
notes on the important parts or follow-up questions, instead of having to try
to scratch everything he narrated as fast as he could speak and write. It just
made so much sense.

~~~
dwater
That sounds similar to the approach my Prealgebra teacher used in 1994. She
had an overhead projector with a roll of plastic transparency sheet attached.
She wrote across the bottom of the projector and then rolled it up as she went
along. Different color pens were available. You could follow along and
understand the process, and there was plenty of time to take notes as the
material rolled up the screen.

~~~
scott_s
I think that all of my math teachers in middle and high school used projectors
with transparencies. It wasn't until college that most math and physics was on
black boards. The major benefit of transparencies is that the teacher was
always _facing the class_. So they could just look up to make eye contact with
students.

I hadn't given it thought before, but I assume transparencies weren't as
present in college because the room a given college class will be is
essentially random. It's not an environment controlled by the person teaching.
in high school and middle school, that was _the teachers '_ classroom. The
teacher stayed in their room, and we moved around. Projectors require more
maintenance (bulbs going out!), and the college teachers would need to lug
around their transparencies and pens. But all college classrooms have
blackboards and some chalk.

~~~
cr0sh
It might also be due to lighting.

Overhead projectors require a fairly dark room, and only work well up to a
certain size and distance. Much beyond that, their light gets too dim, and if
it is a large lecture hall, you need a large projection with very bright light
for everyone to see.

Then there's off-axis people who might find a projector difficult to read. In
a small classroom, both of these issues don't really come into play.

A blackboard, however, can be seen in a brightly lit room, almost anywhere in
the room, even if the room is very large. For the really massive size lecture
halls, you can have multiple blackboards that span the width of the room, plus
sliding and portable ones.

Each system has its benefits and detriments I guess...

~~~
rtkwe
> large lecture hall, you need a large projection with very bright light for
> everyone to see.

And the hard limit on how bright you can make that is that the lecturer is
staring into that light while writing so you can only make it so bright before
it becomes painful or damaging. Anecdotally when I was in elementary/middle
school we'd sometimes have to work things out writing on a projector and it
was tough sometimes and looking up you couldn't really see because your eyes
had adjusted to the brightness of the projector. Maybe they could improve the
lenses to spill less light out but it wasn't back then.

------
Aromasin
I had one lecturer in my 4 years at university that only used a chalkboard,
and most pupils despised him because the pace as which he wrote far surpassed
the rate at we we could sensibly copy notes. We wrote it out, but it gave
little time to actually consider the concept we were learning. The rest of my
lecturers all used PowerPoint presentations for the most part, in conjunction
with print-outs so we could follow along on a projector and write
notes/annotations on the provided sheets.

In my eyes, a hand-out + computer notes (which can later be emailed to the
pupils) is by far the superior teaching method for most students. This is of
course just personal preference, but I much prefer simply sitting and
listening to the teacher while occasionally asking questions - taking in as
much as I can, then copying up the notes later using material provided by the
lecturer so as to commit it to memory. Frantically writing out the notes
during the lecture, then going home and trying to eek out some sort of
understanding from them just never sat well with me.

~~~
magicalhippo
I found the exact opposite when learning math. I need to write it down, and
when presented with Power Point I have to transform it into something I can
understand, and that means I don't have enough attention left to really listen
to the lecturer.

On the other hand, the lecturers that used a blackboard at my uni all had
prepared the lecture, what they wrote was meant to be written in a notebook.
They wrote it at a pace that could easily be followed. This allowed me to go
over proofs as I wrote them down, and I could then ask right away if there was
anything unclear.

I also found several typos (usually a sign error or a missing term) this way,
something which would probably have confused me a lot if I didn't catch it
until I got home.

So, for me, well-prepared blackboard lectures is preferable, at least for math
heavy stuff.

~~~
gowld
Shouldn't you be paying full attention instead of taking redundant dictation
during lecture?

If you weren't stuck with following a chalkboard, typos could be fixed once
and for all time at the source, instead of reappearing at random in every
lecture.

~~~
magicalhippo
But that's the point, I _was_ paying full attention. By writing things down, I
had time to process and think about what I wrote. I had time to fully follow
the derivations. And that's in addition to the reinforcement effect that the
act of writing has (at least for me).

Merely sitting there passively listening would not be paying full attention.

Of course, this required the lecturers to write in a suitable tempo.

------
b_tterc_p
Porcelain whiteboards are, in my opinion, far superior to chalk. Color,
distinct lines, easy to clean with just water (completely with no marks).
Those who complain about whiteboards usually are only familiar with melamine
boards.

I got a big porcelain board for 5 bucks on eBay because one corner was dented.
Best purchase of my life.

~~~
aesthesia
The problem I have with whiteboards, and especially porcelain ones, is that
they are too slippery. Writing on a chalkboard offers a certain amount of
resistance and texture that just feels better than on a whiteboard. This is
also something that you really need a high-quality board to experience. The
texture of cheap chalkboards is not very pleasant either.

~~~
b_tterc_p
I have experienced this but only when it’s wet. The tricky thing is that it
seems impossible to dry it completely with anything but time. So you do need
to wait a good few hours after cleaning with water.

~~~
cr0sh
Use windex or other common glass cleaner sprays; they tend to evaporate very
quickly.

------
impendia
As a couple of commenters noted, a Korean company (Sejongmall) purchased some
of the machinery, adopted the Hagoromo Fulltouch brand name, and recently
started producing and selling chalk. You can buy it on Amazon, for example.

In my opinion (which seems to mostly be shared by other mathematicians), the
quality is quite good -- approximately comparable to the Japanese original.
Also the price is cheaper, $17.00 for a 72-piece box.

We chalk snobs have breathed a collective sigh of relief.

------
FabHK
Reminds me of Walter Lewin's (of MIT) famous dotted lines:

[https://www.youtube.com/watch?v=l789l6np-
qA](https://www.youtube.com/watch?v=l789l6np-qA)

~~~
dmix
Has he explained how he does this?

~~~
FabHK
Yes:
[https://www.youtube.com/watch?v=GhawwXcQsUs](https://www.youtube.com/watch?v=GhawwXcQsUs)

BTW, there are also circle drawers:

[https://www.youtube.com/watch?v=eAhfZUZiwSE](https://www.youtube.com/watch?v=eAhfZUZiwSE)

------
dzink
The affiliate link at the end points to a $139.99 version of the chalk box on
Amazon, when an identical box next to that amazon listing shows at $17. The
article came out in 2015, so seller or amazon or both are possibly scalping
the demand while the article publisher seems to also profit.

~~~
em-bee
is it possible that the seller noticed additional sales from the link and
decided to take advantage and jack up the price?

------
jcurbo
Mirroring some other comments here, my best experiences were with overhead
projectors and document cameras. My high school math teacher would sit on his
desk at the front of the classroom and use an overhead projector with
transparencies on a roll so he could just roll up as he wrote. In college a
lot of professors used document cameras for basically the same approach. I
think it was by far the most effective way to teach math because they could
just write equations etc. out and also face the class, and they didn't have to
deal with chalk or dry erase markers.

~~~
rbanffy
The soothing sound of the overhead projector, the dim light of the classroom
combined with both the subject and the relaxing voice of the teacher were
unbeatable for mid-day sleep during college.

------
michaelmcdonald
Previously discussed on HN:

[https://news.ycombinator.com/item?id=9723202](https://news.ycombinator.com/item?id=9723202)

------
gbronner
I studied under Brian Conrad. He could write on the blackboard faster than I
could take notes, and his lectures were elegant and well-thought-out, if
abnormally fast.

Glad to hear that he's cornered the market on quality chalk!

------
soyiuz
I prefer high-quality markers and whiteboards. As for "toxic cleaning
chemicals," you can use your own recipe to make a mild cleaning solution. Far
less toxic than lifetime exposure to chalk dust.

------
privong
This reminds me some of what I've read about Blackwing pencils (originally
made by Eberhard Faber Company), which were discontinued in 1998. The
originals (NOS) were apparently quite sought after once production ceased.
California Cedar Products is now making a "Blackwing" pencil[0] which purports
to be the "revival", but there is some criticism[e.g., 1].

I have never used an original Blackwing, so I cannot comment on those, but the
new ones are enjoyable to write with. It's similar to the feeling I have when
using fountain pens – they're such an improvement for the act of writing that
I actively seek out reasons to hand-write things.

The specifics of this chalk story versus the Blackwing story are different,
but it's neat to see the passion people have for their writing implements. And
that many of these, admittedly higher-quality, versions seem to be unable to
survive the decrease in hand-written forms.

As for me, I do prefer chalk to whiteboards. I've always been slightly annoyed
at getting chalk on my hands and so think I would have enjoyed using this
chalk if I'd had the opportunity. But I see fewer and fewer chalkboards
around.

[0] [https://blackwing602.com/](https://blackwing602.com/)

[1] [https://blackwingpages.com/facts-fiction-and-the-
blackwing-e...](https://blackwingpages.com/facts-fiction-and-the-blackwing-
experience/)

------
chobytes
I'm not sure why we thought chalk boards needed replacing. White boards seem
generally inferior, and even worse is this newer trend of large computer based
boards.

------
glaurung_
The college I went to had a mix of whiteboards and chalkboards. Even as a
student I preferred the rooms with chalkboards. It seemed like the light on
dark contrast and no glare made them easier to see.

I also find disposable markers to be a bit of an environmental horror. In the
grand scheme of things maybe it's not that much waste, but replacing something
like chalk with a thick plastic non-recycleable marker for little if any gain
is disturbing.

------
wespad
This reminds me of a story I read about 10 years ago of a Japanese
manufacturer of a very specific type and format of scientific lab notebook
that ended production. I think about the story every now and then and go on a
deep dive, but can never find it. Buried in the web.

------
chungleong
As I recall, most of my engineer professors used transparencies and overhead
projectors.

------
cr0sh
Something to throw out:

Do the manufacturers of this chalk (or any chalk) regularly test for asbestos
contamination?

From what I understand, it is kinda the same safety hazard you'd have with
cosmetic uses of talc (for makeup and the like); the risk is low for
contamination, but it is possible - which is why they do testing on talc (and
even then, there is still the possibility of it being present in very, very
low amounts).

I'm just wondering if the same applies to chalk?

------
z3t4
I guess whiteboard pens is a better business, they run out fast and are really
expensive compared to chalk.

------
_bxg1
I could understand how chalk has a romantic aspect to it, compared to
whiteboards. It conjures dusty libraries and hardwood desks. And I think such
things have a larger impact on abstract thought than many appreciate.

But I definitely can't imagine replacing either with PowerPoint, of all
things.

------
Dokibook
It is available on [https://Dokibook.com/p435](https://Dokibook.com/p435) It
is made in South Korea

------
jwilk
Please use the original title.

------
Syzygies
Chalk of Champions (CNN video, May 2, 2019)

[https://vimeo.com/333758769](https://vimeo.com/333758769)

------
OrgNet
If only this chalk was easier to erase then regular chalk (the dust chalk it
creates is also a problem though).

~~~
reikonomusha
This chalk _is_ easy to erase.

------
leemailll
This chalk looks much nicer than the usual one.

------
jbottoms
Chalk and the chalk holder.

------
781
> _“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._

A clean blackboard is not that fun either. To clean it nicely you need to
sweep the whole of it down vertically with a wet sponge. This requires a water
source and it's a messy deal. In high-school there was a daily designated
pupil who was responsible for wiping down the boards and keeping a wet clean
sponge.

~~~
nerdponx
Also the "cleaning fluid" is just isopropyl alcohol

~~~
gnulinux
Is inhaling small amounts of isopropyl alcohol safe? I found conflicting
information online. Apparently it's also used for pipe and vape cleaner.

~~~
klodolph
For questions like these, I would start with the MSDS. While the MSDS doesn't
always answer your questions, they tend to be reasonably conservative relative
to typical use. For example, they sometimes recommend safety gear that people
ignore.

Keep in mind that isopropyl alcohol is available at different concentrations,
and the different concentrations have different MSDS. Here are the hazard /
precautionary statments from the MSDS:

H335 - May cause respiratory irritation P261 - Avoid breathing mist, vapors,
spray. P271 - Use only outdoors or in a well-ventilated area.

Note that "avoid breathing mist, vapors, spray" is not an especially strong
statement.

------
akeck
(2015) - I wonder if production has been revived since then.

~~~
johnnycab
If I remember correctly, the three machines were sold off to different buyers.
Regardless, it is probably far too early to be revived, even under the guise
of nostalgia and perhaps too niche a product, say, compared to the Impossible
project. Although not the same, there are alternatives available:

[https://www.jetpens.com/Rikagaku-Dustless-Chalk-
Accessories/...](https://www.jetpens.com/Rikagaku-Dustless-Chalk-
Accessories/ct/876)

