Polishing while listening to the voice of the raw stone.
The "hand-polishing" technique inherited in Kofu
From Friday, June 26 to Sunday, July 5, 2026, MIN GALLERY will hold a special exhibition featuring five artists and two collectors, themed "Formation."
This exhibition brings together artists who create works with stone and metal motifs, a photographer who meticulously captures the expressions and nuances of earth, and collectors of rare fine minerals and fossils. Each will convey the charm and power of things formed from natural products, using their unique sensibilities and methods.
Today, we introduce Kanna Oshiro, a gem polisher based in Kofu, Yamanashi Prefecture.
Oshiro, one of the few polishers in Japan to inherit the "hand-polishing" technique, is known for polishing gems solely by feel, without the use of jigs. Her work, which involves discerning the individuality of each stone and bringing out its unique characteristics, is not an industrial process but rather an activity akin to a dialogue with nature.
From Filmmaking to the World of Gems
Although Oshiro currently works as a gem polisher, she originally was involved in prop making for film production.
A turning point came when she encountered jewelry through her work. Deeply attracted to the idea that "jewelry is completed when worn by a person," Oshiro moved to Kofu, Yamanashi Prefecture, a city rooted in the jewelry industry. She began her studies at the Yamanashi Prefectural Jewelry College, the only public jewelry vocational school in Japan.
However, she didn't initially intend to become a gem polisher when she started studying jewelry. Oshiro herself recalls, "I mistakenly believed that 'gem polishing was an already complete world, where the standard was to cut stones into uniform sizes and make them sparkle.'"
This perception changed dramatically after meeting Shimizu Kiseki, the company she now belongs to, and her mentor, Yukio Shimizu. She learned that gem polishing was a creative world with unseen possibilities when she encountered the highly expressive "hand-polishing" technique, which involves polishing gems solely by feel without the use of jigs (tools for setting angles, etc.).
Her mentor, Mr. Shimizu, is known as the only polisher in the world who can create the "Kikyo cut" and has dedicated many years to passing on the hand-polishing technique. Learning from his work up close was an experience that made Oshiro re-evaluate her approach to gems themselves.
Bringing out the innate form of the stone
Oshiro's hand-polishing technique involves feeling the entire stone in her hands as she polishes.
Especially in random cutting, by adding bold facets or overlapping fine facets at different angles while observing the stone's condition, unique one-of-a-kind loose stones with distinct rhythms are created.
Her creation process is not solely reliant on intuition. First, she intently observes the stone, contemplating how to best showcase its inherent beauty. Only when the skeletal form of the stone becomes apparent does she begin to work by hand.
She often states that by building the overall expression of the loose stone from the rhythm and balance created by those facets, she is led to lively finishes that exceed her own imagination.
"Sometimes a good facet is accidentally created in an unintended way during polishing, and I try never to miss that moment, as it's the true charm of hand polishing," says Oshiro.
Developing her work by embracing the accidental beauty that appears during polishing. This flexible approach may be what gives Oshiro's creations their unique sense of vitality.
Furthermore, the raw stones she handles daily are a crucial source of inspiration. The contours and growth marks of raw stones, nurtured by nature over long periods. She describes her current ideal as expressing their expansive, organic beauty with minimal intervention.
Instead of imposing a finished form, her underlying philosophy of polishing is to discover the inherent charm of the stone and listen to its voice.
Listening to what nature has created
Oshiro continues to present her work under her personal name "canna oshiro" while learning diverse polishing techniques through her work at Shimizu Kiseki. Her cuts are affectionately known among fans as "Kanna Cut."
In her daily work, she encounters various stones, and these experiences become seeds for new ideas. In her personal work, done on holidays or after hours, she explores free expression unconstrained by size or purpose, based on these insights. The pieces born from navigating between work and creation are imbued with a deep contemplation of the stones themselves.
The Formation exhibition will showcase works born from this exploration.
New works to be unveiled at the "Formation" exhibition.
Kanna Oshiro's work, born on the boundary between the inherent charm of natural raw stones and minimal human intervention, offers profound insights into the theme of "formation." We invite you to experience her creations, born from quietly listening to the stone's innate beauty, at the exhibition.
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Formation — Process and Form —
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Kanna Oshiro
Born in Shizuoka Prefecture. Graduated from Yamanashi Prefectural Jewelry College. Works as a gem polisher while affiliated with Shimizu Kiseki. Inheriting the "hand-polishing" technique, which polishes gems solely by feel without the use of jigs, she also presents her work under her personal name "canna oshiro." She focuses on the individuality of raw stones and forms created by nature, pursuing unique polishing expressions that bring out the inherent charm of the stones.
Text by MIN GALLERY
Photo by Yumiko Miyahama