atelier ST, CAT Opens New Engagement Ring and Diamond Specialist Store in Yoyogi-Uehara

Bridal jewelry brand atelier ST, CAT is opening a new standalone store specializing in engagement rings and diamond rings in Yoyogi-Uehara. The shop, named -u- atelier ST, CAT (ユーアトリエエスティーキャット), is scheduled to open on June 27, 2026.

A New Standalone Store Driven by Growing Demand

Since pivoting to a bridal-focused business in 2023, atelier ST, CAT has reported consistent growth, with profits rising 25-fold over three years. Alongside expanding demand for custom wedding rings, requests for engagement rings and diamonds have also increased — prompting the decision to open a dedicated space.

The new store is located a 3-minute walk from the brand's main store in Shibuya-ku Uehara, and will operate independently as an engagement ring and diamond specialist. The separation is intended to allow for a more focused and personalized ring selection experience for each couple.

Lab-Grown Diamonds and a Wider Range of Designs

A diverse lineup of engagement ring designs, with options spanning materials and diamond color

Alongside natural diamonds, the new store marks atelier ST, CAT's first introduction of lab-grown diamonds. The lineup ranges from statement pieces featuring larger or colored diamonds to understated everyday styles, with a broadened range of designs maintained at the brand's standard of quality.

Ring settings are handcrafted by artisans at the atelier ST, CAT workshop, with fully bespoke options available — from the setting style to the ring's shape and surface finish.

An Atmospheric Space Designed by MILESTONE

Entrance featuring iron with hand-applied aging treatment

A circular glass window at the back of the store offers a view into the atelier

The interior was designed by MILESTONE, the studio behind popular venues including "Kabi" and "AC HOUSE." The space contrasts organic curved arches with the raw quality of hand-treated iron, creating an atmosphere that is both calm and intriguing — with cave- and space-inspired details throughout. A circular glass window at the back offers a glimpse into the adjoining atelier. Plastered walls and layered lighting complete a quietly refined environment that reflects the brand's aesthetic.

About atelier ST, CAT

Ring crafted with longevity and wearability in mind

The handmade quality of the designs evokes

Founded in 2014 by former fashion editor Seiko Hayashi as a handmade jewelry brand, atelier ST, CAT introduced wedding rings in 2022 and completed its transition to a full bridal brand in 2023. All pieces are handcrafted in the brand's own Yoyogi-Uehara atelier, combining artisanal technique with a design sensibility rooted in fashion jewelry.

The brand's distinctive aesthetic — described as evoking "unfinished spaces that expand with a couple's life together" — is defined by the subtle, natural irregularities of handmade craftsmanship. In spring 2026, Akiho Kano, who has played a central role as designer and artisan since the brand's early days, took on the role of Creative Director.

From the Creative Director and CEO

Creative Director Akiho Kano

Creative Director Akiho Kano: "Choosing an engagement ring can feel daunting for many people. That's exactly why we wanted to create a place where the process of choosing itself feels natural and enjoyable. We hope to deliver the time you and your partner have built together, in the form of a ring."

CEO Seiko Hayashi

CEO Seiko Hayashi: "By expanding into lab-grown diamonds and a wider range of designs, we aim to offer engagement rings unlike anything available before. We hope each person finds a ring that makes them feel, 'I've finally found it.'"