KOHKOH (Koukou), a jewelry brand operated by Castem Co., Ltd. (Headquarters: Fukuyama City, Hiroshima Prefecture; President & CEO: Takuo Toda), will host a pop-up shop at JR Nagoya Takashimaya (Nakamura-ku, Nagoya City) from Wednesday, June 17, 2026, to Tuesday, June 23, 2026. This marks the brand’s first event in the Tokai region.
KOHKOH discovers new value in 'mother shells'—oyster shells discarded in large quantities during pearl cultivation—and transforms them into sustainable jewelry. The brand has earned high acclaim for its works that leverage patented pearl cultivation techniques and precision processing technologies, including winning the Best Jewelry Prize at New Jewelry TOKYO, Japan’s largest designer jewelry event.
At the event, KOHKOH will unveil nine new pieces, including the brand’s first 'Light Series' earrings, and display and sell approximately 100 items, including cameo jewelry crafted from mother shells and pearl creations made with proprietary technologies.
Event Information
【Dates】 June 17 (Wed) – June 23 (Tue), 2026 10:00–20:00
【Venue】 JR Nagoya Takashimaya (1-1-4 Meieki 1-chome, Nakamura-ku, Nagoya) 1st Floor, Women’s Accessories Event Space
【Featured Items】
- Modern cameo rings with delicate engravings on mother shells
- Brooches featuring cameo-shaped pearls cultivated using proprietary pearl farming techniques
- Rings combining precision-cut gemstones and pearls
- Earrings combining 'Powder Pearl'—formed by sintering powdered mother shells—and natural pearls
Total of approximately 100 pieces
Product Highlights
Think_Ring
A cameo ring carved from carefully selected mother shells, blending skilled handcraftsmanship with digital technology. The delicate profile cameo is layered over a transparent blue topaz, creating a sense of depth.
While honoring the beauty of traditional cameos, it is elevated into a modern form. A piece with quiet presence.
Materials:
18K gold, mother of pearl, blue topaz Size: 26 × 16 × 4 mm
Powder Shell Earring_01
Born from the brand’s founding vision: 'to use the mother shell itself as jewelry until the very end.'
The 'Powder Pearl' series grinds pearl mother shells into powder and sinters them into new spherical forms reminiscent of pearls. By giving new value to materials previously difficult to utilize, KOHKOH achieves both circular manufacturing and unique beauty.
Materials:
Silver, shell powder, ceramic powder, pearl, rhodium plating Size: 18 × 10 mm
New Collection
The pop-up will debut nine new pieces.
In addition to baroque-style earrings featuring silver balls on mother-of-pearl shells, the collection includes rings combining pearls and gemstones, and the first-ever earrings from the brand’s signature 'Light Series.'
Please visit the venue to experience these pieces in person.
About KOHKOH
KOHKOH (Koukou) is a jewelry brand launched in 2023 by Castem, a precision metal parts manufacturer. The brand is led by Takatsugu Kojima, an internationally active jewelry artist and board member of the Japan Jewelry Designers Association.
Focusing on 'mother shells' discarded in large quantities during pearl farming, KOHKOH creates sustainable jewelry that combines environmental responsibility with design excellence. By applying Castem’s 3D shaping technology, the brand achieves free-form pearl cultivation that defies the traditional notion that 'pearls must be round'—a technology protected by patents.
Committed to creating 'jewelry like no other' that sheds light on social issues, KOHKOH has won the 'Best Jewelry Prize' (2024) and 'Audience Award' (2024, 2025) at New Jewelry TOKYO, Japan’s premier designer jewelry event.
About Castem Co., Ltd.
Castem specializes in manufacturing and selling precision metal components for industries including railways, machine tools, and medical devices, using lost-wax precision casting and MIM (Metal Injection Molding) technologies. Since 2017, the company has expanded into planning, manufacturing, and selling consumer products. It has gained attention for creating unique anime, manga, and sports-related goods, such as metal sculptures of handprints of famous athletes and idols, and Poké Ball-shaped insect cages. The company also operates in origami airplane and agricultural ventures, and is advancing innovations like 'Digital Cast®,' a casting method using diverse 3D printers, and full-color 3D figurine production.
Castem Website: https://www.castem.co.jp/
Contact
KOHKOH Contact: Kamimura
E-mail: info@kohkoh-jewelry.com
Official Website: https://kohkoh-jewelry.com/
Online Store: https://store.kohkoh-jewelry.com/
Official Instagram: https://www.instagram.com/kohkoh_jewelry/
FACT BOX
- Source: PR TIMES
- Category: Event