Why mathematicians are obsessed with this luxury chalk

Business Insider

Hagoromo has been described as "the Rolls-Royce of chalk." The formerly Japanese, now Korean brand's chalk is known for its smooth consistency, its vibrancy, and being nearly dust-free.

Transcript

00:00These wiggly little tubes will end up as sticks of Hagoromo chalk.

00:07You'd be forgiven if this writing utensil doesn't make you emotional,

00:12but the world's mathematicians might disagree with you.

00:15From a very personal point of view, I love that feeling.

00:20It's been said that the secret ingredient is angels' tears,

00:26and legend has it it's impossible to write a false theorem with it.

00:31Business Insider was unable to confirm or deny these claims.

00:35What is certain is that fans of this chalk swear by its smooth performance,

00:40consistency and colour range, which are unmatched by cheaper brands.

00:45You can buy a box of 12 white pieces for $10.50 on Amazon,

00:51while Crayola's version goes for as little as 62 cents.

00:56These days, it's made in South Korea,

00:59but back in 2015, the chalk almost disappeared forever

01:04after the original Japanese company announced it was shutting down.

01:08I did remember scavenging for chalk.

01:13So, as other companies' chalk sales decline,

01:16how is this expensive chalk still selling out?

01:20And what keeps Hagoromo heads coming back for more?

01:28It sort of like melts on the blackboard.

01:31That's the feeling as you go, it's just like melting very, very gently,

01:35and it just writes a lot better.

01:40Alvaro Lozano Robledo is a professor of mathematics at UConn

01:44and would only ever use Hagoromo chalk if he had his way.

01:48Like there was some video that I made about,

01:50it was like Gollum and My Precious, you know, the one ring,

01:54but it was like me, you know, just like looking at pieces of chalk

01:58that somebody left behind or something.

02:05So, I started making more and more videos

02:08that were like jokes about mathematicians and chalk.

02:12The lore that surrounds this brand runs deep.

02:17It's almost like you can taste it.

02:20You don't have to eat it on purpose, but you can taste it.

02:24But the real secret to making Hagoromo chalk distinctly smooth,

02:28pigmented, easy to erase, nearly dustless,

02:32and therefore more expensive,

02:34is its special formula and production methods.

02:38It's these qualities that keep mathematicians reaching for the brand.

02:43Making a stick of Hagoromo chalk starts in one of these industrial mixers.

02:49The main ingredient is calcium carbonate,

02:52which is a compound often referred to as chalk.

02:56It makes up 70% to 80% of the recipe.

03:00Cheaper chalks will sometimes be made with gypsum,

03:03a mineral used in plaster as the base.

03:13With other types of chalk,

03:15the piece of chalk will break, pieces will fly,

03:19but also a lot more dust is being created as you go along.

03:24This one, as I write, just like a couple of dust specks flew away,

03:30but otherwise everything stayed on the board.

03:34If you don't remove the salt,

03:37you know the smell of the sea.

03:40So if you add salt,

03:42you can smell the sea,

03:44but if you don't remove the salt,

03:46you can't smell the sea.

03:48So if you don't remove the salt,

03:50you can't smell the sea.

03:52If you don't remove the salt,

03:54you can't smell the sea.

03:56If you don't remove the salt,

03:58you can't smell the sea.

04:01The last known ingredient is kaolin,

04:04a natural clay essential for making porcelain.

04:08Adding this helps bind the ingredients.

04:11The rest of the Hagoromo formula is confidential.

04:15All we know is its consistency.

04:31It's these materials that Shin Hyeong-seok

04:35says differentiate Hagoromo from its competitors

04:38and bump up its price tag.

04:41At this point, white chalk is ready to be shaped into sticks,

04:46but there's an extra step for colourful chalk.

05:01In South Korea, Hagoromo's white chalk

05:04costs 201 per stick.

05:07Regular colours cost 401,

05:10and the fluorescent line costs 601.

05:19Typical fluorescent pigments

05:21contain harmful chemicals

05:23that can be harmful to the environment.

05:26Typical fluorescent pigments

05:28contain harmful chemicals like formaldehyde,

05:31but Hagoromo uses premium pigments

05:34without those substances.

05:36Hagoromo has seen the demand for these colours grow

05:39as online lectures have become more popular

05:41over the last few years.

05:49Alvaro needs a multitude of colours when he's teaching

05:52to visualise complex ideas.

05:56So here I actually coloured in the triangle in purple,

06:00so I'm going to do that also here,

06:02so you see the triangle,

06:04that that triangle in purple is the same one

06:08that we had before.

06:11And just as importantly, he needs them to erase.

06:16If you use other brands,

06:18other cheaper brands like Cariola,

06:20if I wrote this on colour,

06:23it would not come off, you know,

06:25for like a week.

06:27Colourful chalks with more abrasive formulas

06:30tend to leave deposits on the board

06:32that muddy the clarity of whatever he wants to teach next.

06:35It was amazing,

06:37the first time I tried with coloured chalk with Hagoromo,

06:40it erases just like the white chalk does.

06:45Once they're mixed,

06:47white and colourful chalk are treated the same way.

06:50This batch will be left to dry out in a maturation room

06:53for about a day and a half

06:55before it's ready to be rolled and shaped.

07:10Much of the equipment used in this process

07:12was specially developed or repurposed

07:14to make Hagoromo chalk,

07:16like the machine that kneads the dough

07:18before it can be moulded into sticks.

07:28Then, these freshly cut lumps are moulded by a machine

07:32specially designed by Hagoromo's former president,

07:35Watanabe Takayasu.

07:49The machine forms thicker tubes

07:51than the average chalk manufacturer.

07:54Inside, the dough is compressed

07:56so the final texture is firm.

08:19The extruded dough is then cut

08:21and left to air dry for up to a day.

08:49The sticks bake in the kiln

08:51at 70 to 80 degrees Celsius

08:53for about eight hours.

09:19The average stick of chalk

09:21would be ready to package and ship at this point,

09:23but Hagoromo takes the extra step

09:25of branding and coating its chalk

09:27with another specially developed machine.

09:45The stamped sticks are then clamped

09:47and dipped in a special coating

09:49that keeps the dust off your fingers.

09:54When they're used side by side,

09:56the difference between coated and uncoated chalk

09:58is immediately noticeable.

10:01Can you use some of that chalk on the board

10:03and show me why it's different?

10:05If I must.

10:11It's a little rougher to handle.

10:13I'm already getting more dust

10:15just on my hands

10:17just from using that piece of chalk

10:19just for one equation.

10:22Alvaro is an official Hagoromo

10:24social media ambassador.

10:27I started making videos on TikTok

10:30and because writing with Hagoromo chalk

10:34is sort of like a meme about mathematicians,

10:37I would make bits about chalk.

10:42And then at some point,

10:44maybe I should contact them.

10:46And they said, yes, you can be an ambassador.

10:50It's a simple arrangement.

10:52He posts about the brand online.

10:54And then they send me, from time to time,

10:56they send me a box of chalk.

10:58So I have a lot to go around

11:00and that makes me happy.

11:04But a plentiful supply

11:06was not always guaranteed.

11:08When the original owner, Watanabe Takayasu,

11:11announced that he intended to shut down

11:13Hagoromo's only factory in Japan in 2015,

11:17Alvaro and his fellow mathematicians felt...

11:21Devastated.

11:22And this is starting to ration

11:25what chalk I was going to use.

11:28Now I want to keep these for research talks.

11:32And if I had to teach undergrads

11:34some calculus, then oh well.

11:36I'm going to have to use the bad chalk for a while.

11:40Some people went as far

11:42as to buy lifetime supplies

11:44in anticipation of the closure.

11:46I don't think anybody here

11:48went so crazy about it

11:50to get a huge box,

11:52a huge amount of boxes

11:55to last us through the apocalypse.

11:58But you had your last supplies

12:00and that was whatever you had

12:02that had to last you through,

12:04I don't know, the end of your career, I guess.

12:06Emergency supplies of chalk

12:09in case the factory was going to close.

12:13And it nearly did.

12:15Takayasu was ill

12:17and having a difficult time finding a successor.

12:25But the course of that side job

12:27led him to form a relationship with Takayasu.

12:40Young-suk wasn't exactly looking to take over,

12:43but that visit got him thinking.

13:10Takayasu was moved by Young-suk's passion for the brand,

13:13but he originally discouraged Young-suk from taking over.

13:40So Young-suk bought the company

13:42and the machines.

14:03It took over six months

14:05and 16 shipping containers

14:07to get everything from Japan to South Korea.

14:10Eventually, staying true to Takayasu's formula

14:13and production methods paid off.

14:16I can't tell the difference.

14:18I think it still feels great

14:20and much better than anything else that I've tried.

14:25Chalk usage has been declining internationally for some time.

14:29But the unique challenge here

14:31is that Hagoromo can't keep up with demand.

14:38It takes about three days

14:40to make a stick of Hagoromo chalk,

14:43and much of the process requires a human touch.

14:51But any change in the quality of the product

14:54and the quality of the product

14:56can be a great help to consumers.

15:07Any change is a risk

15:09when the brand's current success

15:11is thanks to honouring tradition.

15:30If the 2015 transition is any indication,

15:33as long as Young-suk can maintain the level of quality

15:36that consumers have come to expect,

15:38they will be grateful to get their hands on it.

15:41I love that feeling.

15:43I love the feeling myself as I'm drawing things

15:47and how neatly I can write things down,

15:52how precise I can do my lines,

15:55how I know that it's not going to,

15:57as I draw that, it's not going to fade.

16:06Young-suk Choi

16:08Young-suk Choi

16:10Young-suk Choi

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