The teCsture Encyclopedia · Straightening · The Japanese family
Japanese systems
Japan's family spans classic shukumo kyosei — permanent thermal reconditioning invented in 1996 — its lighter cousin the straight perm, and the modern wave: sansei acid straightening, sannetsu acid-heat treatments, and the kamishitsu kaizen "hair quality improvement" culture that dominates Tokyo menus today.
The shared philosophy: diagnosis first, precision always.
Level of change
The Zoltan teCsture Scale™ runs from 1, the tightest pattern, to 10, straight — one ladder, ten levels. What a treatment does is move you a number of rungs. That distance is the job, and it is what the work should be priced on: the level of change, not the bottle.
This family spans the entire ladder. The lightest tiers move you about one level; the middle two to five; permanent straightening four to seven. Deciding the distance first is what stops the conversation being about brand names.
One family, every distance. Which tier you need is a question about how far, not about which bottle.
Work out your own code first
Before any of this is a booking, it is a reading: what your hair is, what it has already had, and how much change it can carry. The Zoltan teCsture Scale™ gives you one code for all three.
The family explained
Two eras, one discipline. The classic era gave the world permanent glass-straight hair through Yuko and Liscio, executed in millimetre sections with strand-checked chemistry — the technique every other country's straightening descends from. The modern era solved the classic era's limit: acid systems working at low pH now straighten coloured and even carefully bleached hair that thio chemistry could never touch, while sannetsu treatments occupy the semi-permanent slot, and kamishitsu kaizen wraps the whole hair-improvement philosophy into Japan's best-selling menu word.
Names and native script
- Japan
- 縮毛矯正 shukumo kyosei (permanent thermal reconditioning); ストレートパーマ sutorēto pāma, everyday ストパー sutopa (the straight perm); 酸性ストレート sansei sutorēto (acid straightening); 酸熱トリートメント sannetsu torītomento (acid-heat treatment); 髪質改善 kamishitsu kaizen (the umbrella)
- USA and UK
- Japanese hair straightening, thermal reconditioning, TR
- China
- 离子烫 lizi tang — the derived category
- Hong Kong and Taiwan
- 負離子 fu lizi
- Korea
- 매직 스트레이트 magic straight — the sibling system
The treatments in this family
The Japanese straightening guide — the definitive guide to thermal reconditioning, the Yuko and Liscio story, the acid renaissance, and who this craft is really for.
The straight perm (sutopa) — the faster, lighter Japanese service.
Acid straightening (sansei) — the permanent low-pH breakthrough for coloured hair.
The sannetsu acid-heat treatment — Japan's semi-permanent acid tier.
Kamishitsu kaizen — the hair quality improvement philosophy itself.
The derived systems abroad: hair rebonding, the mass-market export, and Korea's magic straight, the finish-philosophy rival.
How to choose within the family
Healthy hair chasing permanent glass finish: classic thermal reconditioning. Coloured hair wanting permanent straight: the modern acid (sansei) route — the family's genuine 2020s breakthrough. Damaged hair not ready for permanence: a sannetsu-style acid treatment or repair-first kamishitsu kaizen work. The choosing rule Japan itself teaches: pick the diagnostician, not the menu item — a salon that studies your hair for fifteen minutes before quoting is the product you are actually buying.
Family rules that never change
Full chemical history disclosed, strand tests always, roots-only on regrowth, colour two weeks after, and deep suspicion of any quote under three hours — precision cannot be rushed, and rushing is where every horror story in this family begins.
Free guide
Japanese straightening: the care that keeps it
The washing, the protein-moisture balance, the regrowth junction and the first-days rules — written for hair that has been through this family. Sent as a PDF, no cost, no follow-up sales.
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What it looks like
Four images: one from each tier in the family, and what regrowth looks like on the permanent one. Photographs coming soon.
Zoltan's note
I learned this family from the inside. Yuko Yamashita trained me herself, and in 1999 I became the first person in Europe allowed to do the system outside the Yuko Academy. I worked in their Curzon Street salon here in Mayfair, I ended up managing it, and then I taught the system on their behalf.
What Japan gets right is the order of work. The diagnosis comes first, the product comes last, and if the reading says no then the answer is no. Everything else in this family — the fine sections, the strand checks, the honest timings — follows from that one habit.
So do not choose between these by name. Decide how far you want to move and how long you want it to last. The name at the end of that is my problem, not yours.
Questions
What does kamishitsu kaizen actually mean?
Literally "hair quality improvement" — the umbrella phrase on modern Japanese menus covering acid treatments, repair systems and straightening work aimed at healthier-behaving hair. It is a philosophy more than one product: diagnose, treat minimally, improve cumulatively. Western menus have no real equivalent yet.
Is acid straightening better than classic Japanese straightening?
Different tools. Acid (sansei) systems are gentler and colour-friendly — the reason previously untouchable hair is now straightened in Tokyo — but demand even more skill to judge. Classic thio systems remain the benchmark on strong virgin hair. The stylist's diagnosis outranks the chemistry choice.
How is Japanese straightening different from rebonding?
Shared chemistry, different culture: Japanese technique is diagnosis-led, millimetre-sectioned and strand-checked; rebonding is its faster, price-driven export. Results can look identical — risk profiles rarely do. You are choosing a discipline as much as a treatment.