Report December 2025
There are many ways to condition jute rope for shibari. The type and quality of raw material, batching % content, type and piling time, and any additional coating all affect methods and results. We only use the best fibre grown at our selected farms in the geographical area Jat. The region that consistently provides the most stable firm, good colour, length and luster raw material. Also the most expensive.
Microstructurally, a cellulose jute cell grows laterally to 18~20µ, 1.4~4mm long, made up of a double-wall, middle lamella, and lumen void. Strength is in hemicellulose and lignin bonds between outer criss-cross microfibril walls, and inner wall fibril spirals. These porous walls make jute aggressively hydrophilic, readily absorbing water into the spongy middle lamella and central lumen void, causing up to 30% swelling.
Rope from cabled strands of countertwisted yarn spun from jute fibre has a level of hairiness and fibre loss, and nap during use. Untreated, it can feel dry, scratchy and tickle. To mitigate this, users condition their ropes.
Before introducing Vegetable Oil Treated rope more than a decade ago, other ropes contained JBO – a cheap, readily available petrochemical derivative which replaced whale oil in the early 20th century. Oil batching is necessary to lubricate and bind fibre, making it stronger, softer and pliable for effective yarn production. Inorganic JBO at ~0.85 specific gravity is absorbed slower than soybean oil (~0.92).
Tests deduce mineral JBO stunts, especially the middle lamella, making fibre wiry and less compressable, explaining why it can be laid looser without generating compression waves through machinery. Hydrophilic action sucks liquid through cell walls into the middle lamella – the compressible mass, expanding into the lumen void, and outwards, making fibre fatten. Conditioning, in addition to attempted JBO removal, provides deeper colour, softer feel and reduces hydrophilia.
Switching to jute in 2000, JBO content lengths bought in Tokyo weren’t very good and stunk. Internet searches recommended boiling and hanging without mentioning tension, and I destroyed the rope. Replacing with 100m from a rope store in Kyoto, better results were achieved using adequate tension when drying, then rubbing in beeswax and singeing. But it was still agro-industrial rope with JBO batched poor material and production quality.
Aoi Sayo handmade a set to her special treatment. I don’t know the entire process. An educated guess it was cold-soaked in water and sun-dried under strong tension. Bāyu loading explained feel and heft, and would’ve been applied and hung to soak in several cycles. Bāyu is made from the synovial sack conditioning a horse’s mane. Tsubaki tea tree oil coating gave the colour, blocked from penetrating horse oil laden cells. A cold beeswax rub-in with final blue-flame singeing to melt sealed the rope. Time, effort and materials cost beyond commercially viable. It was made with skill, patience, pride and friendship, without profit. Kitagawa is now considered the expert in rope processing, has similar results, but keeps his method secret.
Business needing increasing supply, Kinoko sent me to Ogawa, and I had to understand how to turn cheap Chinese JBO farm rope into something useable. Japanese friends suggested boiling, drying under tension, oiling, waxing and singeing. The colour stain in process water and resultant scum should be a warning, and we now know boiling weakens cellular bonds, and after processing those crackling sounds under load are catastrophic rips in cell walls.
Because it’s a mineral oil, JBO requires detergent to try to remove some of it. A good method was to machine wash at 60°C in a cotton laundry bag with a little detergent and some fabric conditioner. But it was still arduous and time-consuming.
Ero Ouji had an improvement by soaking in undrinkable cold sake overnight. High glucose alcohol at greater specific gravity penetrates and dissolves JBO better than cold water, inhibits microbial breakdown, and evaporates faster, making conditioning steps easier. ~10% bioglycerol in water may have a similar effect. Heating JBO releases toxic gases, so it wasn’t long before others were following suit with cold-soaking.
VOT batched rope permitted tumble drying as a simpler, dry method to dislodge loose fibre and soften, removing all the hassle of wet processing. Changing from bees to berrywax blended into a ‘butter’ with jojoba oil made the entire product vegan, the result silky rather than sticky, and became an easy method to infuse conditioning. Use of a cotton laundry bag reduced butter loss. Singeing doesn’t produce the black soot of mineral distillate.
Many jute yarns are coated for anti-slip (eg. natural latex in carpet backing), anti-bacterial (eg. lowering decomposition in feed sacking), and/or to reduce hairiness and fibre loss (eg. polyvinyl alcohol). These impact conditioning.
This month we experimented with an alternative method based on Japanese conditioning from over a decade ago using JBO-free KOUMANAWA 60. First we loaded the rope with bāyu cream. Beware of cheap Chinese versions in plastic tubs cut with water that should be avoided. Real Japanese bāyu comes in 80g jars. Loading was made by coating and rubbing in over 4 cycles, allowing the rope to fully absorb and dry between each. Then we hand coated with jojoba oil, and noted how little is required as the bāyu had blocked the jute fibre’s hydrophilic action. We then liberally rubbed in cold, dry berrywax, ensuring full coverage before finally singeing to melt and blend in the wax to the surface to create a seal.
The result was beautiful, colour only slightly darkened, diameter gain ~6%, and weight gain ~18%, fibre loss and nap almost eliminated. However, for an 8 x 8m set conditioning cost ~100€ and took 3 weeks, confirming it isn’t commercially viable.
