Yu-Su-Ru: The Thousand-Year-Old Japanese Ritual TikTok Keeps Reinventing

Every few years, a skincare trend goes viral and is treated as if it were invented on the app where you saw it. Rice water ice cubes are the current version of that story. The honest version is a thousand years older, and better.

Home-remedy note: this article describes cultural and historical context, not medical advice. The traditions described here inform how rice water is used today; they don’t constitute efficacy claims.

The Heian court, on a spring morning around the year 1000

The Heian period (794–1185 CE) was the most style-conscious era in Japanese imperial history. The women of the emperor’s court — the same women who produced The Tale of Genji and The Pillow Book — cultivated hair that reached the floor, skin the color of pale jade, and a beauty aesthetic so refined it still informs Japanese cosmetics marketing a millennium later.

Their tool for doing this, on the regular, was rice water. The practice was called Yu-Su-Ru (ゆする) — literally “rinse,” specifically the rinse of water that had already been used to wash rice. Rice was the staple grain; the rinse-water was a household byproduct; the use of it for hair and skin was practical, free, and effective enough that it became ritualized.

The practice survived the collapse of the Heian court, migrated into provincial domestic life, and was preserved in the beauty practices of geishas and courtesans who inherited many Heian-era aesthetic traditions wholesale.

What they were actually doing

By the standards of modern cosmetic science, Yu-Su-Ru was a reasonable protocol:

• Rinse uncooked rice with water.
• Retain the cloudy, starch-rich rinse water.
• Apply to hair (for smoothness and shine) and to skin (as a gentle cleanser and toner).
• In some regional traditions, allow the rice water to ferment for a day or two before use.

What the Heian ladies didn’t know — because biochemistry hadn’t been invented yet — is that they were delivering inositol, ferulic acid, allantoin, amino acids, and (in fermented preparations) kojic acid to their hair and skin. That’s the same list a 2022 review in the Journal of Cosmetic Dermatology would catalog a thousand years later. They were correct for reasons they couldn’t articulate.

The sake brewery moment

Skip forward to the 1970s. Japan’s sake industry is mature, highly ritualized, and — crucially — full of elderly workers who spend their days with their hands submerged in fermenting rice.

Cosmetic-industry researchers noticed something: the workers’ hands looked unusually youthful. Specifically, they looked younger than the workers’ faces. That was the experimental hook. The scientists collected and screened yeast strains from the fermentation process — reportedly 350 of them — and isolated one particular Saccharomyces strain whose ferment filtrate had the most promising effect on skin.

That filtrate was trademarked as Pitera, launched in SK-II’s Facial Treatment Essence in 1980, and became the foundation of a $4B+ skincare franchise that’s still selling the same hero product, now at $185 for 230 milliliters. The bottle has changed remarkably little in 45 years.

The Heian court → geisha tradition → SK-II through-line isn’t marketing invention. It’s a real lineage. The ladies of the imperial court were using the low-tech version of what SK-II now sells as the high-tech version. The mechanism — postbiotic metabolites from rice-based yeast fermentation — is the same family of biology.

The Korean lineage, running parallel

Korean rice-water skincare is not an imitation of Japanese practice. It’s a parallel tradition with its own vocabulary and regional variations. The term sal-pit-mul (쌀뜨물) — literally “rice-washing water” — is the Korean name for the cloudy rinse liquid, and it’s used in folk skincare as well as in traditional medicine contexts.

Modern K-beauty brands have reached back into this tradition deliberately:

• Beauty of Joseon takes its name and visual identity from the Joseon dynasty (1392–1897) and leans heavily on rice and ginseng.
• I’m From built its brand around Korean agricultural ingredients and has a rice toner that is basically the distant commercial cousin of traditional sal-pit-mul.
• Skin1004, Haruharu Wonder, and Innisfree have all integrated rice ferment into mainstream K-beauty product lines.

This isn’t a case of brands inventing a story. The story was there for a thousand years and the brands, correctly, drew from it.

So when TikTok tells you they discovered rice water

They didn’t. You didn’t. Nobody on the app this year invented this.

What TikTok did contribute is real — the ice-cube form. The specific ritual of freezing rice water into cubes and rubbing them on the face is, as far as we can tell, a 21st-century social-media innovation layered on top of the traditional use. That’s worth noting. The cold-plus-rice-water combination doesn’t have a thousand-year history; it has a few years of Instagram and TikTok.

That doesn’t make it a bad idea. It makes it a legitimate modern variation on an ancient theme, in the same way that espresso is a legitimate modern variation on the ancient theme of coffee.

The right way to honor the tradition

If you’re going to adopt this ritual, here’s how to do it without being a jerk about its history:

1. Credit the lineage. “Korean rice water skincare” or “a Japanese beauty tradition” takes one sentence. It’s accurate and it’s courteous.
2. Don’t claim you invented it. You found it; it’s been around.
3. Don’t exoticize it. It’s rice and water, not a mystical secret. The Heian ladies didn’t treat it as magic; they treated it as a practical household practice. That’s the correct register.
4. Don’t pretend it’s better than it is, or worse than it is. The compounds are real. The effects are modest. A thousand years of use isn’t proof it cures anything; it’s proof it’s gentle, tolerable, and not harmful — a bar most new skincare ingredients don’t clear.

What you can pull from the tradition

A few practical things the historical record supports:

• Fermentation matters. The historical use of aged rice water (what we’d now call “fermented rice water”) is consistent across Japanese, Korean, and Chinese traditions. This isn’t incidental — the historical users figured out empirically that day-old or two-day-old rice water worked better. The modern pH-and-kojic-acid explanation confirms what they already knew.
• Daily isn’t the tradition. The documented use patterns are periodic rather than daily. This aligns with modern dermatology guidance that rice water is best used 3–4 times per week.
• Hair and skin, together. The tradition uses rice water for both. If you’ve only been using it on your face, consider the hair application — the evidence base for hair is if anything stronger.

The bottom line

Rice water skincare is one of the longest-running, best-documented, most-successfully-modernized beauty practices in human history. It’s cheap, gentle, mildly effective, culturally rich, and — when prepared correctly — completely safe for most skin. Whether you apply it with a cotton ball as a Heian lady did or rub it on in cube form as your FYP shows, you’re participating in the same basic ritual the imperial court invented.

The mechanism is real. The tradition is honored. The ice is new.

Sources

1. Madewithine. What is Rice Water & Pitera? Is It Good For My Skin?
2. SK-II. Facial Treatment Essence — Pitera origin.
3. Grokipedia. SK-II.
4. Zamil DH, et al. Dermatological uses of rice products: Trend or true? Journal of Cosmetic Dermatology, 2022.
5. INCIDecoder. Galactomyces Ferment Filtrate.