Mari Katayama stares out from the centre of the photograph, looking like a mannequin with a Louise Brooks bob. Lit by fairy lights and surrounded by all her personal artefacts, she is wearing a cream corset and reclining in a Louis XVI-style loveseat. Beside her sits a lifesize doll, a handsewn replica of herself – and on the floor in front, decorated with images of leaves and butterflies, lie her discarded prosthetic legs, each shoe adorned with a sparkling light.

Katayama was born with tibial hemimelia, an extremely rare condition that stops bones in the lower legs from fully developing, often leaving them foreshortened. In her case, the condition also caused club feet and a cleft left hand that resembled a crab’s pincers. Consequently, crab motifs recur in the work of the Japanese artist, who was also born under the sign of Cancer.

“You can’t separate my body from my work,” she says, when we meet at Gateau Festa Harada, a sweet factory in Gunma that doubles as a gallery and is hosting a retrospective of her work. “But,” she insists, “I’m not making art out of my disabilities.” However, given that she uses her body as a sort of living sculpture, she acknowledges that the subject is complex.

Still in her 20s, Katayama is a star in the making, her work already attracting notice from collectors and curators in Europe and America – a rarity in the vibrant but insular world of Japanese contemporary art. Remarkably, Katayama never set out to be an artist. Her intricately embroidered and stuffed objects – inlaid with lace, seashells, hair, crystals and collaged images – were made purely for her own amusement. And art was far from her mind when she began to take portraits of herself. “I was only taking photos to show my friends on MySpace what I’d made,” she says.

The plaster-cast body mould with leather skin. Photograph: Mari Katayama

The retrospective is one of two major Katayama shows taking place in Gunma, to the north of Tokyo. The other, an exhibition of new work called On the Way Home, is at the prefecture’s Museum of Modern Art. In person, Katayama is nothing like the fierce, singular character suggested by her photographs. She is sweet, unassuming and girlish, sitting in her wheelchair with a face mask on to ward off a cold, yet rising to almost 6ft tall on her prosthetic legs when she gets up to open a box full of the seashells she uses to decorate her work.

Her retrospective is called 19872017, the year of her birth to now, which reflects how entwined Katayama’s life and work are. “Creating and living are the same thing for me,” she says. “There is no separation. I really don’t know where my work ends.” She grew up 45 minutes from the sweet factory in a small city called Ota, where she still resides in an apartment that also serves as her studio. In fact, it is more of a constantly evolving installation.

Simon Baker, curator of photography at Tate Modern, was struck by Katayama’s work when he first saw it at the Unseen photography fair in Amsterdam last year. “It really stood out,” he says. “There are ideas about identity and performance, as well as obvious references – art historical references to previous artists.” He cites Cindy Sherman, Jeff Wall and Matthew Barney. At the same time, he adds, Katayama’s work stands alone. “She’s touching on things without being derivative of them. There’s also this incredible personal story.”

The artist as a little girl. Photograph: Mari Katayama

As a child, Katayama wore special shoes buckled to her legs with braces, which meant she couldn’t wear regular clothes. She recalls three generations of women in her family – great grandmother, grandmother and mother – constantly sewing clothes for her, and encouraging her to make her own. “I learned to hold a needle and thread before I could hold a pencil,” she says. “It was like: if you want something, you make it.” Sewing became second nature.

Inevitably, her disability set her apart at school. The bullying started in third year. Far from offering sympathy or support, Katayama’s teacher suggested that she had provoked her tormentors by looking at them with disdain. The bullying got so bad she began to skip school and, for a while, was even kept away by her parents.

At the age of nine, of her own volition, she decided to have her lower legs amputated. It seems a remarkably mature decision for somebody so young but Katayama says it was entirely practical: “It was a choice between being bound to a wheelchair for the rest of my life – or being able to walk but losing my legs. I chose to walk.” Afterwards, she underwent a year of training that seemed to last for ever. Relearning how to walk on prosthetic legs instilled in her a discipline and focus that, she believes, carried over into her artistic practice. Able to wear regular clothes and shoes, she became interested in fashion, hoping she could fit in by dressing like other kids. But the bullying continued.

When she was 16, Katayama caught the eye of Tatsuya Shimada, then a fashion student, now a stylist for Vogue Japan. He was putting together his graduation show, using unconventional, non-professional models of all ages and body types, and came across Katayama through her blog. “She told me she was drawing and playing bass in a band,” recalls Shimada. He dressed her for the catwalk in a style that can only be described as Caledonia by way of Harajuku – a kilt customised with pink carnation ruffles with hats piled up on her head, accessorised with a corsage of bagpipes. He asked her to draw fairies on her prosthetic legs, but instead she drew a thistle rising from her instep. “It was a mixture of beautiful colours with an element of the grotesque,” says Shimada.

Some of Katayama’s decorated prosthetic legs. Photograph: Mari Katayama

Katayama thought her newly tattooed legs were just the kind of unique fashion statement that would win her friends at school, but this didn’t happen. “It made the situation worse,” she says. “Nobody wanted to have anything to do with me.” She had, however, hit upon a way of expressing herself. “It made me realise that words and gestures weren’t the only way to communicate.” Inspired by punk, she dyed her hair green and shaved off her eyebrows. “It was my way of saying, ‘Leave me alone.’”

All the while, she was sewing and making things. Her first self-portraits were taken in her bedroom wearing a blond wig with a pair of ornately embroidered, stuffed legs placed in front of herself as if they were her own. “They were the legs I lost,” she says. “That was how I imagined them. Right from the beginning, I saw myself as one of the raw materials to use in my work.” She does not see the photos as depicting her real self, though. Rather, they’re a form of role-play. “I couldn’t experience any of those things children do, like trying out my mother’s high heels, or walking around in oversized shoes, or playing the heroine in a school play.”

A teacher suggested entering her work in the Gunma Young Artists Biennale. Katayama won the Encouragement award and, for the first time, art seemed a viable option; by 23 she was a student at the prestigious Tokyo Art Institute.

The 2014 installation You’re Mine typifies the amount of intricacy in her work. She had a plaster cast mould of her body made, then covered it in a handsewn patchwork leather “skin”. She made a wig for the mannequin out of her own hair and, in place of a face, is a dressing-room mirror with lights that an actress uses to transform herself. Growing up, Katayama felt that she had to mimic others in order to be accepted and conform: “It expresses the idea that I’m absorbing things like a sponge from people who look into the mirror.”

Inspired by Botticelli … Katayama on the beach at Naoshima. Photograph: Mari Katayama

A recent trip to Naoshima, a tiny island in the Seto Inland Sea of southern Japan, opened her eyes to Naoshima Onna Bunraku, an all-female style of traditional puppet theatre. “The dolls for bunraku don’t have legs,” says Katayama. “They use elbows and hand movements to express themselves instead. It made me think how versatile hands are.”

She photographed the hands, printed them on to material, and sewed these new creations into a multi-armed, many-handed entity. It was the first time a body other than her own has featured in her work and she confesses to feeling somewhat baffled by it. “Foreign bodies had entered my work,” she says, and recalls how she would photograph herself lying on the beach, phone in hand, with the arms and hands of this alien creature sprouting from her own like the legs of a crustacean, a pose inspired by Botticelli’s Birth of Venus.

As she was completing the project, another new body presented itself, this one living inside her. Katayama is pregnant – and tickled that her child will be born under the sign of the crab, though she is uncertain how this will affect her art. It is, however, unlikely to alter the principle that has underpinned all her work, an ethos she sums up with the words: “All human bodies – including ones like mine that have been altered by human hands – are perfect.”

• Mari Katayama: On the Way Home is at the Museum of Modern Art, Gunma, Japan, until 20 March. More details: shell-kashime.com.

