Tattoo artist Remy painstakingly injects tiny dots of pigment into Koki Hatanaka's bald scalp to mimic hair follicles, performing a grey-zone cosmetic procedure increasingly in the crosshairs of Japanese health authorities.
Japan bucks a global trend by viewing permanent make-up as the domain of medical professionals, and has ramped up threats of criminal prosecution against anyone else who practices it - like the 44-year-old Okinawan.
Industry insiders insist that their craft, from make-believe hair to filled-in eyebrows and lip tints, is an artistic pursuit more befitting tattooists and hairstylists.
But in a country where body art has long symbolized yakuza gangsters, these cosmetic tattooists' safety and sanitary protocols are not enough to dispel skepticism.
"It's a complete mystery to me why they keep saying this constitutes a medical practice," Remy - his professional name - told Agence France-Presse (AFP) as he used a fine needle to ink 28-year-old Hatanaka.
The procedure known as scalp micropigmentation (SMP) is "hardly invasive" and "so painless that clients sometimes even fall asleep," while requiring sophisticated aesthetic talent, Remy argues.
And it is an important job: a sudden onslaught of alopecia - the medical term for hair loss - once plunged Hatanaka into despair.
"I didn't even want to go outside," the marine sports instructor, whose style now passes for a buzz cut, told AFP.
"If I hadn't done this, I wouldn't have become brave enough to strike up conversations with strangers," he said.
"I'm more confident in myself now."
A landmark Supreme Court ruling in 2020 declared traditional decorative tattooing a non-medical act, welcome news for an industry long run by artists with no clinical training.
But the same did not apply to SMP, which has "an established history of doctors' involvement," a health ministry official told AFP.
The use of needles makes it a "risky enough practice that it can hurt human bodies if done without medical expertise," she said.
The ministry has repeatedly warned, most recently in December, that criminal complaints can be filed against unlicensed practitioners, "essentially signalling arrest," healthcare law expert Akihiro Saotome told AFP.
That notice likely had a "significant chilling effect" on these businesses, he said.
In reality though, a slew of medically unlicensed cosmetic tattooists continue to operate openly, having even rallied together at a flamboyant convention hosted by Remy's SMP brand, Scalp Ink, in Okinawa last month.
Dozens of beauty specialists, including from South Korea, Vietnam and Sweden, deftly inked the scalps, eyebrows and lips of their models, surrounded by towering banners depicting each participant as oceanic royalty in coral crowns.
They argued that, if anything, permanent make-up is even less medical in nature than tattooing for artistic purposes, because it does not penetrate the skin as deeply.
Otherwise, they said, both follow the same hygiene safeguards, use needles to insert pigment into human skin and are practically indistinguishable.
"I'm doing nothing I should be ashamed of," Tatsuki Miyahira, an Okinawa tattooist who also performs SMP, told AFP. He has no medical licence.
If raided, he said, he would "give them a full tour" of his workplace and explain every safety precaution.
He added that if Japan officially declared SMP art, "I think I can hold my head even higher."
Experts say Japan and South Korea were long among the few countries that penalised permanent make-up by non-medical personnel - until last year when Seoul passed a landmark law decriminalizing it.
"Why is it only Japan that still can't do this?" asked hairstylist Michiko Shinmasu, 50, who doubles as an eyebrow tattooist.
The lack of legal endorsement "makes my clients (for eyebrow work) feel as though they're doing something wrong. They're like, 'this is grey-zone, right?'" she said.
Some think Japan's complicated relationships with tattoos - historically etched on criminals and then favored by mobsters to assert their rebellion - fuel official distrust of the practice.
Even today tattoos are often banned in public places like hot springs, and Japanese are far less inked than their Western counterparts, although this is changing.
"Nowadays lots of people get their bodies inked just for fashion" in Japan, SMP business operator Yasuaki Sameshima, 41, told AFP.
"But tattoos of a different kind existed before. I think their negative image is spilling over and shaping the way SMP is perceived today."
Despite repudiating medical control on his profession, SMP guru Remy agrees it risks infections if done poorly, warning against a completely unregulated approach.
In fact, he campaigns for the systematic accreditation and training of all tattoo artists - cosmetic or not - in an industry he says remains an ungoverned "grey zone".
"Every country has some kind of licence specifically for doing tattoos, but Japan hasn't created that," Remy said.
He founded the Japan Tattoo Hygiene Association, with the ultimate goal of making its programme mainstream and even mandatory for the opening of tattoo parlours.
"I believe that's the best way to protect clients and to ensure that tattoos are done under proper hygiene management."
