Sin is a man of many talents. Author of Year of the Bakushi (2016) and The Psychology of BDSM & Rope Bondage (2019), he’s also been a frequent contributor to Kinbaku Today. He has interviewed many well-known Kinbakushi, documenting the history of rope bondage as it evolved in Japan. Sin is also a development engineer with several intellectual properties to his name, the founder of Amatsunawa, and now KOUMANAWA. Quite a resume.
Sin has been involved in BDSM for over forty years. His first kink experience involved tying his spouse in 1984, and he’s been tying ever since. He’s performed regularly on the underground circuit since 2011 and is now sharing his self-developed methods for rope bondage based on a foundation gained from his Japanese rope teachers and friends.
I spent some time with Sin in a video call to find out what he’s been up to, and what his plans are for this new venture he’s pioneering that will be of great interest for anyone that uses rope.
It’s really good to interview you again. The last time was with Ugo-san of SMPedia and Mark BeShibari back in December 2020. In that three part interview, you discussed the current state and future of rope bondage. Can you bring the readers up to speed on what you’ve been doing since then?
Sin: So much has happened. The pandemic, global conflicts, etc. I suffered some misfortunes, but kept plodding on.
I’ve had a relationship with Marusan Japan for over a decade, but only identified them as the optimum jute rope manufacturer in late 2019 after a dash to a rope store in Kyoto. In March 2020, we planned a meeting at their production facility in Bangladesh, but four days before, the flights were cancelled and national borders closed due to Covid. I couldn’t interact with production and demonstrate what we require from a shibari rope, which led to some problems.
A customer approached with an investment offer in 2021, and I relinquished control of Amatsunawa. Following a series of incidents that became obviously connected, my lawyer advised me to walk away. I won’t comment because it prejudices court action. It was tough losing my baby, but the world moves on. I got a job and tried to rebuild my life.
Then Marusan contacted me asking if we could work together, and KOUMANAWA was born. Kouma in Japanese rope industry terms means ‘Jute’, and Nawa, ‘Rope’. The name was their idea. They could see my vision for this market. I understand they made their own investigations and ceased supplying Amatsunawa.
You started looking for the ideal rope for shibari in part due to your own interest in rope bondage, but also because a rope partner suffered anaphylactic shock from JBO.
Sin: I don’t know if it was anaphylaxis. I’m not a doctor. I hadn’t completed the Takatekote when she became dizzy and her wrists and forearms reacted. Big red lumps where the rope had been. The hospital gave her medication. It spurred me to discover the cause, which quickly became apparent was JBO. I thought I’d boiled it all out. It was quite shocking.
Where were you getting your rope from that it caused that reaction?
Sin: From Ogawa, a small general rope store in Tokyo like many all over Japan. The owner got the Material Safety Data Sheet from their supplier producing in China. When you read JBO shouldn’t be heated above 38°C (100°F) to avoid release of toxic hydrogen sulfide and alkyl mercaptans that can cause respiratory collapse, it’s not biodegradable and harmful to aquatic organisms, it’s a wake-up call. Further investigations of scientific papers highlighted how JBO can cause skin and liver cancer.
That is actually very alarming.
Sin: These ropes are not intended for tying people, but for farming where it doesn’t matter. People have tried many methods to get JBO out. Boiling, steaming, baking, etc. But it stays resident in the rope at some level.
Let’s face it, the smell isn’t very erotic. Talking to the Japanese fifteen years ago, they had no concept of JBO. It was just available rope, and wherever you got it, whoever manufactured it, the yarn was batched with JBO.
You found out how prevalent JBO is in the rope manufacturing process. Were you actively looking for non-JBO rope?
Sin: I thought I’d find JBO-free rope off the shelf. I visited suppliers all over Japan, and in 2015, ordered 500kg without JBO from a factory in Aichi. I believed they’d manufactured it, but later discovered it was sub-contracted to Marusan. Double shipping Bangladesh via Japan to Europe was very expensive.
And so Amatsunawa was founded. Because you were trying to find the perfect JBO-free rope.
Sin: It started because I wanted better rope for myself. Three years of transporting spools in my extra Business Class luggage, and then importing increasing amounts by air and then sea freight, my accountant explained it was too much for the authorities to ignore, and I founded Amatsunawa as a sole trader in 2014. Profit was reinvested into R&D, learning about jute, finding an alternative to JBO, and how to develop and design rope specific for shibari. I thought manufacturing rope would be fairly simple, but it’s far more complicated than I’d ever imagined.
Twenty years ago there was some amazing jute Asanawa which disappeared around 2011. I guess it ran out. I’d been gifted some by Aoi Sayo in Osaka, and set out to reverse engineer it by researching old patents to find how it had been made. The trick turned out to be in the yarn stage.
You can’t make good rope from bad yarn, or good yarn from bad material, and nothing happens without minimum order quantities, so I had to open it up for everyone. Third-party yarn mills can’t make it because their quality control regimes are practically nonexistent. Nobody’s asked for yarn for this application before. We’ve used what was available.
Over the years I’ve been approached by manufacturers all claiming they can produce the rope quality, but when samples arrived they were only good to trash. I don’t respond anymore. It’s a waste of time.
It is an international effort. The Japanese working with you and the team in Bangladesh. All geared to producing rope for bondage?
Sin: The breakthrough came when Marusan, with three decades of their own yarn supply nightmares, scams, quality and reliability issues decided enough was enough, and invested in a self-built, state-of-the-art yarn mill. I own the Trade Secret, and became their consulting engineer and exclusive global distributor. They head-hunted Ando-san, a jute expert with whom I closely work. There’s a lot of development ahead. Not just for the shibari market.
We don’t use any JBO in our yarn mill, which went operational November 2024. We developed KI-grade yarn (KOUMANAWA Ito) designed using the best material with almost zero impurities, adjusting soybean batching oil content and spinning to improve bulk filament compressibility while increasing longitudinal strength. This permits us to loosen rope lay ratios while retaining balance and durability.
Nobody’s ever been able to do this before, and create a real shibari rope, because yarn supply has always been unreliable and designed for very different applications. Nothing is achievable without managing the entire supply chain and processes, specifications, tooling and quality control regime.
We put together our team of production management, jute procurement, hacklers, and machine operators at both the yarn mill and rope factory, and trained them. Everyone understands the reasons why things have to be done a certain way. While we’ll never be able to control weather conditions causing variations in availability and fiber color each season, we’ve locked down everything else. The shibari market demands the highest quality, no JBO, availability and consistency, which because of the yarn had been impossible to guarantee before.
The first milestone is achieved – the rope structure. As with any product and process development, we had to try counterintuitive things to learn what specifications make little difference when slackened to be able to tighten others. This rope is the pinnacle of what’s possible with jute, and will become available sometime next year after we’ve serviced bulk wholesale orders.
Koumanawa seems to focus on selling rope wholesale. I’ve also noticed on the website, people can buy smaller quantities of rope.
Sin: We sell to anybody. Currently, we can’t split spools, so samples are difficult because everything goes through fulfillment centers where they don’t have facilities to cut and package. We’re considering sample packaging in the future.
For palletized orders we offer attractive discounting. We have customs brokerage at the factory, which means for non-EU we ship direct, eliminating double costs so the landed price is cheaper. EU orders piggyback in our containers.
Our business model has altered to become global distribution for the factory, so we’re going to close the webshop. E-commerce is the realm of our reseller customers. Product will still be available for B2C customers directly.
How much better is Koumanawa’s quality compared to the rope you produced prior to 2021?
Sin: Light years. Because we’re now procuring, we can secure best quality raw material. We optimized the yarn design, so the rope is more flexible and durable. The material has no plant debris that scratches or punctures skin. It’s just jute and soybean oil. Nothing else – a stable product with good longevity and wear abrasion, feels beautiful and is a superb color. And it‘s so much easier, cheaper and faster to condition.
Colored rope for shibari is popular. Are there any plans to sell Koumanawa rope that is offered in a variety of colors?
Sin: Ando and I are working on it. I have a system concept. It’ll be the last stage of development funded from sales.
That investment is strictly to produce colored rope for shibari? Or is it for other applications too?
Sin: We’ll be dyeing raw material before it’s batched and spun, and have markets for colored yarn outside shibari. We have a goal, but it’s probably two years away.
I briefly touched on your first experience with rope for bondage in the introduction. Tell us more about that first time use of rope.
Sin: I’m the eldest son of a nautical trade family. I can’t remember a time when rope wasn’t in my hands. I worked holidays on tugs, pleasure boats and on the locks. Around thirteen on the school bus I fantasized tying a girl a few seats away so I could have access to the forbidden fruit. At nineteen, I came across rope bondage as a photoshoot theme in a late-1970s Scandinavian porn magazine. Then in 1984 my wife asked if we could play. I had red cotton rope, maybe with a little engine oil on it in the cupboard. I tied her to the bed and realized how much we both enjoyed the experience, how it regulated my libido as hers built, so we reached our ultimate pleasure together. We loved doing it.
What was the rope scene like in 1984?
Sin: There was no scene or resources. I taught myself. Pre-internet, draconian UK pornography laws and strict social morality sent people to prison for what we now term BDSM. It was something you did privately. Exposed, you’d be ostracized as a sexual deviant, criminal or mentally ill. We enjoyed what we did in the bedroom and nobody knew.
What was your first exposure to the Japanese form of rope bondage?
Sin: Business travel took me to Japan thirty years ago, and in 2000, I met a kinky Japanese girlfriend who introduced me to the scene. My activities had to remain clandestine, so Japan became my secret playground the other side of the world. But I didn’t think of bondage as from any nationality. I just got on with it. I lurked on Jimi Tatu’s AdultRopeARt Yahoo group, but remained anonymous.
I started going to SM clubs, happening bars and pink theater, and began making friends such as Aotsuki Nagare, Nawanojyoh, Kasumi Hourai, Kinoko, Kazami Ranki, Yoi Yoshida, Bingo, Saikatsu, Otonawa, Tesshin, Kanna, etc.
I’m most associated with Ero Ouji, who many Japanese consider the Kinbakushi of his generation. Our professional lives overlapped, and our common approach and motivation for the ladies to return affection for what we do produced a strong bond. We shared ideas, especially my rapid psychological conditioning. He loved it and started doing it too. I get my love of Takeshibari from him. In a way, we fed each other’s kinbaku. He retired due to serious ill health in 2019, and I miss his generosity, dignity, integrity and honor.
In the early 2000s I worked in Kita-ku and stayed in Ikebukuro where I’d go to clubs, sit quietly and observe. I may have seen Akechi, but wouldn’t have known who he was. I saw Nureki at an event, but didn’t approach him. I rue never knowing Tsujimura Takeshi or Matsui Kenji, for me two pillars of kinbaku.
When you were in Japan, did you take lessons?
Sin: I saw Aotsuki do a tie, couldn’t figure it out, and wanted him to teach me. Getting to Osaka wasn’t practical, so I asked Ero Ouji. He said he didn’t teach and suggested Shigonawabingo (Ero Ouji later covered at SM Club Jack Rose when Otonawa went to Aotsuki’s Titty Twister).
Bingo agreed. I believe I was his first student. We arranged models and a translator, and went through the protocols and philosophy before even touching a piece of rope. This added to the Japanese business etiquette I’d already been mentored in by the presidents of two corporations. I love Bingo’s free-flowing creativity, understanding of time and space dynamics, anatomy, balance and mind games.
I took instruction as part of an interview with Yukimura, declining a teaching certificate. It spawned a slow process of grasping the psychology of libido in restraint. I had more one-on-one lessons with other Kinbakushi, gaining a blend of approaches and philosophies, and found this very rounding – helping me evolve my own path, rather than mimicking claimed patterns that had all been done before anyway. I went on to learn Anma and Ampuku, and adapted them into the adventure of kinbaku.
You built upon the foundation that you were taught and added your own methodology to rope bondage.
Sin: You have to develop your own style to be genuine. Part of my education was witnessing the adventure in its entirety at pink theater – tying, psychology, philosophy, and handling of balance, timing and aesthetics, like Ikebana. I think of partners as something of great beauty, like flowers. I ‘arrange’ them in rope rather than hang them like salami.
What else did you learn about the Japanese approach to tying?
Sin: Japanese society contains a huge amount of cultural manners – Shigusa. How to behave, how to approach situations, how to react. These things are very important.
It’s critical to understand how different the Japanese are, even to Chinese and Korean neighbors. Their references are completely unlike ours: social history, perspective, attitudes towards the erotic and suffering, their logographical writing which is highly contextual, etc. Believing we fully understand is misguided. It’s the same the other way. They don’t really understand us either. Culture and language are big barriers. At some point you realise you know what you don’t know, and cease making assumptions.
Lest we forget, the Japanese cut themselves off from the world, missing the printing press, industrial revolution, photography, etc. So when Commodore Perry sailed into Tokyo Bay everything came overnight. I joke with them that if aliens don’t come from outer space, then they probably come from Japan.
Their obscenity laws had an impact on why Japan is the go-to for rope bondage. During the Tokugawa Shoganate, Christianity was the most obscene, and could get you executed. Anything erotic didn’t factor so much. After WWII, the Supreme Command of the Allied Powers gifted freedom of expression (US First Amendment rights), so long as you didn’t criticise said Allies, or the atomic bombings. Red light districts always existed in Japan. Now many were servicing US troops.
Weak regulation permitted the Japanese to produce publications with diverging specialties, including kinbaku. In the land that gave us video, it wasn’t too long before photoshoots were filmed, and evidence suggests many terms for ties were created by Nureki for VHS sleeve notes he was selling to sex shops.
You can’t imagine being able to witness kinbaku in Soho, Pigalle, De Wallen, or the Reeperbahn in those times without arrests and a tabloid frenzy. Yet in Kabukichō or Roppongi, while still somewhat underground, it was entirely possible.
And so the Japanese got forty years on us, developing, evolving, and producing nearly all the resources. The difference in their tying is related to their differences in psyche, context and perspective. Challenging for us to fully comprehend.
Now you have perfected the ideal rope for shibari, what’s next?
Sin: During Covid, Yoi Yoshida told me I should give up my secrets and help the younger generations. I started to socially interact and try to understand their viewpoints, which are very different because I come from a world that doesn’t exist anymore.
I’ve been performing live kinbaku sessions for 14 years, where the audience want to believe it’s real and not just show. When I first tied in clubs and at parties nobody had seen it before. People were fascinated. Since then so many have got into it, which is great. I encourage it. It’s everywhere now, and predominant in kink forums.
I’ve always suffered from imposter syndrome, even when I was in bands. After I performed at ARCADIA Osaka and Black Heart Ginza earlier this year I got really embarrassed when guests called me ‘Sensei’. It made me feel uncomfortable.
I stopped doing the big latex discos when riggers started doing them for free. Promoters love free. Now we only perform where we control the atmosphere. No flashing lights or loud music, where the voyeurs are near enough to understand the adventure. I don’t interact much with the rigger scene. After so much time in Japan, I’m an outsider in their world and don’t really understand them. They probably don’t understand me either. My area is Kannōnawa – deep, sensual, sadoerotic, intense, euphoric. Not really appropriate in the mainstream.
Since 2021, I’ve taught professional dominatrix whose customers want to try rope bondage. Teaching lightweight ladies to tie larger, inflexible men requires a different approach. I’ve been asked to teach advanced kinbaku, including in Japan, and giving it serious consideration.
I’ve learned a lot by teaching, because I’m putting stuff into words to explain what I’ve always done automatically. But I can’t see how to teach advanced kinbaku in a group. How can you focus on everyone at the same time? You need to get into each individual’s mindset – why the partner wants to be tied. What are their motivations, desires, taboos, fears? What are the same of the one tying? I always learn something new, and I love this because I’m eternally curious to discover more.
Teaching at this level is best done one-on-one. For groups it may have to take the form of a demonstration where I tie in real time, untie, then tie slowly explaining every detail and invite students to feel tension, etc. I need a model who can be expressive to say, this is what’s happening, this is what I feel. When students can fully absorb a more nuanced approach it’s rewarding to see their renewed enthusiasm.
What do you think about people teaching that their way is “the way” to tie?
Sin: It’s a mistake to say how it’s supposed to be done because it’s highly individual and unavoidably intimate. If we’re only copying, we’re not advancing. You may want to tie for the erotic, for beauty, provide suffering, or do it for sports, stamina, meditation, etc. I have my intrinsic way, but to say it’s right or wrong… the wrong way is when it’s non-consensual, abusive and/or causes harm. The right way is where everyone’s enjoying and nobody’s hurt.
I am concerned about what psychologists call Narcissistic Guru Syndrome where characters believe they’re above others, charge excessive fees, reject alternative viewpoints, and demand obedience to their methods. They’ll violate boundaries, engage in abusive behavior, and sabotage perceived competitors to maintain themselves as sole truth. It’s a poison that’s been behind many abuses. But nothing new. The same nonsense occurred when yoga came to the west.
If someone’s interested in taking lessons from you, do they need to be local? Do you teach via live video?
Sin: Video is possible from the philosophical side, but for the practical would be unwise.
I don’t teach invented dogma, or say you have to copy me, because you’re not me. I encourage students to find themselves. Figuratively, I teach how to tie shoelaces. Once they can tie them, they have to learn to walk in their own shoes. I help with those early steps, and remain available when they want to discuss things they’re discovering, sometimes things I haven’t come across or thought about.
If someone is local to Munich or able to come in person, how to you decide if they’ll benefit learning from you?
Sin: It starts with a consultation. Sometimes you get those who treat it like assembling furniture, and that’s going to waste both our time. Dominatrix are great students, because they get it so quickly. I guess they have to, to be successful at what they do.
I need students who can see the depths – how far it goes, how to make it exciting, spontaneous, euphoric. How to be in the moment with the partner. To read every situation as it changes by the second. It has to be individual because if it’s just copying, it’s like picking up an instrument and playing somebody else’s song exactly the same way. But that’s just my opinion. There are plenty of people who’ll say “I’m doing so and so’s style”, which so and so copied from somebody else anyway.
I’m also available to travel to teach.
Are you collaborating with anyone at the moment?
Sin: I try to help when anyone asks, including the Japanese. Well, the good ones, because there are some dubious characters too. Some already loose on an unsuspecting west. I’m troubled by the lack of admission.
I find locations for Kasumi Hourai with a strong female coordinator who aren’t connected to questionable individuals.
I help Bingo get students because he’s not very well. I always loved his approach of adapting to fit the rope to the person rather than the person to the rope.
When asked, I’ve always hooked up westerners with places to go and people to meet in Japan. I like connecting people. Being helpful.
What are your thoughts on the current rope scene in Japan?
Sin: Unfortunately, pink theater is dying out, and with it, the bizarre and erotic I adore. My generation, and the ‘old school’ Showa-era bondage we enjoy is slowly disappearing.
It’s cynical how a few have realised Gaijin are easy money. I never held with the dogmatic schools, styles, grandmasters and deshi nonsense created after 2005, and I’d never hang on the coat-tails of the deceased.
If you wear rose-tinted spectacles, you can’t see the realities because you’ve not been deeper and wider on the ground over a long period and may take things at face value from limited sources. We’re living in a world of alternative facts, where armchair experts regurgitate cultural appropriation and invented history, and erase reality.
Some think shibari comes from penal use, ignoring the blindingly obvious. Of course rope was used for tying, even killing prisoners. But it takes an odd mind to focus on this rather than the theatrical and sadoerotic evolution from punitory suffering. We play with historical torture themes, but never think we’re re-enacting eg. the Spanish Inquisition, or the martyrdom of St. Andrew. If you question, you’ll be vilified heretic. Is it because some struggle to admit to themselves they’re perverts?
Of all the interviews I conducted, only the tip of icebergs were published. Many more never got approval due to Japanese etiquette about not saying anything negative. Sometimes fear of retribution. I’m in the unenviable position of knowing far more than is good for me.
I still find inspiration. Kinoko and Shishiwaka are the best of the younger generation. Kasumi brings a feminine element which men can learn so much from – a ritualistic wabi-sabi style. It’s enchanting to watch her facial expressions, and the way she constructs ties to, as she would put it, enjoy the beauty of suffering. Kitagawa piqued my interest, and we get along really well. I’ll spend more time with him next time I’m there. Maybe even interview him.
The Japanese I ask are inquisitive about western diversification from the sadoerotic into new forms of shibari. They’re not negative about it. Maybe a little confused. But we can all see how it’s heading mainstream.
Younger Japanese are emerging that, in my opinion haven’t mastered it yet. Some technically tie very well, but there’s still something missing. Being Japanese doesn’t mean you’re naturally good, and I see westerners who are better. Empathy is key to really understand kinbaku.
We need maturity and life experience to see beyond the rope. When you can competently rig, there’s so much more to explore. I’m on that path and I’ve only been tying forty-one years. Still a beginner, still learning. I find it fascinating how deep this thing goes. And it keeps going and going. A learning curve without end. I love it.
Useful Links:
Koumanawa website: https://koumanawa.com/en/
Sin’s Instagram: @sinbakushi
Sin’s website: https://kannounawa.com
About the Author:
Darkly_Dreaming is a Miami based practitioner of kinbaku. His rope journey began in 2018, and he has received the guidance of three talented bakushi allowing him to incorporate elements from their teachings as he develops his own style of expression with rope. He has written several reviews for RopeFlix and is a contributor to Kinbaku Today.
Follow him on Instagram @Flowerandrope
