Researchers have detailed how artisans transform the Okinawan banana plant into Bashofu—light, breathable fabric woven from stiff fibres. The study explains how age-specific fibre selection, intricate processing, and structural modification yield a soft, durable textile that stays cool and comfortable, connecting centuries-old craftsmanship with modern materials science.
- Artisans’ tactile skill allows them to separate warp and weft strands purely by touch, identifying subtle differences invisible to the eye.
- The study aimed to document Bashofu craftsmanship in detail and to preserve this traditional knowhow while guiding future sustainable-fabric research.
- Published in Scientific Reports, the paper “Morphological Analysis of Musa balbisiana var. liukiuensis fibers for Kimono-Grade Bashofu in Japan” grounds centuries of craft in modern plant science. The study was authored by Koji Koizumi, Yayoi Maehara, Toshio Sasaki, Hitomi Shinzato and Yoko Nomura of the Okinawa Institute of Science and Technology,
THE STUDY: The research provides a detailed structural explanation for Bashofu textiles, revealing how traditional fibre handling achieves softness and breathability. Using imaging, microscopy, and tensile tests, scientists traced how artisans’ tactile methods correspond to measurable fibre traits, confirming centuries-old craftsmanship as an early model of sustainable material engineering. The researchers note their close collaboration with the Bashofu artisans, whose materials and insight made the scientific study possible.
- The study links historical craft practice with modern materials science, grounding empirical knowledge in plant morphology and mechanical data.
- Findings confirm that fibre selection and preparation directly affect cell-wall thinness, enabling flexibility and airflow unique to Bashofu.
- Researchers emphasise that preserving this heritage could advance contemporary sustainable-textile innovation through lessons drawn from indigenous design.
THE CRAFT: Bashofu is a traditional Okinawan textile crafted from banana plant fibres through 23 meticulous processing steps. Artisans carefully classify leaf sheaths from the Itobashou plant, with the finest grade called Nahagu—an especially thin, light kimono fabric made exclusively from two to three inner sheaths per pseudostem. This exceptional material provides coolness during Okinawa's subtropical summers, overcoming banana fibre's naturally coarse texture through skilled traditional techniques.
- Bashofu production dates back to at least the 16th century during the Ryukyu Kingdom period, establishing it as one of Okinawa's most enduring traditional crafts.
- The Japanese government recognised Bashofu as an Important Intangible Cultural Property in 1974 under the Law for the Protection of Cultural Properties.
- Ryukyuan royalty particularly favoured thin Nahagu kimonos as summer garments, valuing both their cooling properties and aesthetic beauty during humid months.
- Contemporary production centres mainly in Kijoka district, Ogimi village, northern Okinawa, though the craft faces decline due to material shortages and dwindling artisan numbers.
- Nahagu fibres are further separated into weft (Nuki) and warp (Hashi) threads by artisans after unwanted parts are removed through the U-biki process.
- Despite careful fibre separation processes, Bashofu textiles maintain consistent plain weave structures and unchanging twisting patterns, making fibre quality the primary determinant of fabric characteristics.
- Scientific research from plant anatomy and ethnobotanical perspectives remains limited, hindering efforts to increase kimono-grade material production through modern understanding.
INSIDE THE LOOM: Bashofu production relies on intricate manual techniques that transform the banana pseudostem into fine thread. The study focuses on pseudostems from 3-year-old plants, where the innermost Nahagu fibres are soft yet strong enough to weave. Artisans separate layers from the Itobashou plant, identifying inner Nahagu fibres for strength and softness, while outer Waha layers serve for interior textiles. Each stage — stripping, washing, spinning, and weaving — demands precision, patience, and intuitive knowledge preserved over generations.
- The artisan distinguishes fibre quality entirely by feel and colour, separating strands invisible to the eye and even discriminating between Nahagu fibres used for warp and weft, ensuring the kimono’s characteristic texture and resilience.
- Imaging analysis confirms that Nahagu fibres have distinctly thinner cell walls than Waha, proving that artisans’ tactile judgements mirror measurable structural differences in strength and pliability.
- Creating one kimono requires fibres from nearly two hundred pseudostems, revealing the immense manual effort, attention to detail, and sustainable reuse of plant material in every garment produced.
CRAFT MEETS EVIDENCE: The study validates the sensory precision of Bashofu artisans, confirming that traditional methods are not anecdotal but scientifically sound. Imaging and tensile data show that tactile judgements about fibre age, texture, and strength align with measurable structural differences, proving that this heritage craft anticipates modern sustainability principles by integrating material efficiency, thermal comfort, and sustainable design sensibility.
- Researchers describe Bashofu as a cultural and scientific treasure, one that bridges intuition and quantifiable process while redefining sustainability through lived, local knowledge.
- The honeycomb-like fibre network channels moisture away from the skin, ensuring breathability, durability, and comfort across Okinawa’s hot, humid summers — a natural performance design evolved over centuries.
- By documenting every stage, OIST scientists not only preserve a fragile tradition but demonstrate how indigenous design logic can guide future innovation in sustainable, bio-based textile materials.
WHAT THEY SAID
We have a close relationship with the people who keep the art alive, and we are very thankful for the materials they have provided us with, considering how difficult they are to create. We have much to learn from Bashofu. The honeycomb structure of Bashofu fibers effectively leads sweat away from the skin through water diffusion, not to mention that both the process and product of Bashofu are highly sustainable.
— Dr Yoko Nomura
Researcher
Okinawa Institute of Science and Technology
The artisan uses the feel and color of the material to detect the difference in the individual fibers when separating out strands from the pseudostem. Our imaging analysis has shown that Nahagu fibers have significantly thinner cell walls than Waha fibers — something which is invisible to the naked eye. And yet, the artisans separate these threads based on touch and color, even discriminating between Nahagu fibers used for weft and warp.
— Dr Koji Koizumi
Scientific Imaging Section
Okinawa Institute of Science and Technology
