Why mathematicians are obsessed with this luxury chalk
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.
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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