J-one Co., LTD.

About J-one Co., LTD.

Japanese Jewelry OEM/ODM Manufacturer Combining Heritage Craftsmanship with Integrated Production | J-one Co., Ltd.

J-one Co., Ltd. is a Japanese jewelry manufacturer whose roots date back to 1905. The company specializes in jewelry OEM/ODM production and the creation of original jewelry collections, helping brands bring their designs to life through skilled craftsmanship and comprehensive manufacturing capabilities. With workshops in Tokyo and Kofu, Yamanashi Prefecture, J-one also works with its Bangkok workshop in Thailand to meet a wide range of production requirements.

One of J-one's key strengths is its commitment to high-quality craftsmanship supported by experienced artisans. The company carefully manages each stage of production, from design consultations and model making to casting, finishing, stone setting, quality inspection, and delivery. For model making, experienced artisans with 20 to 50 years of experience combine CAD technology with traditional handcrafting to capture the details and character of each design. Their expertise also contributes to consistent quality in mass production, particularly during the critical modeling and casting stages.

J-one sources diamonds directly from supplier facilities in Mumbai, India, without going through intermediaries. Three staff members holding GIA gemological qualifications inspect diamonds individually to help maintain consistent quality. The company also specializes in micro-setting, a precision stone-setting technique that uses magnification to handle small diamonds and create delicate, intricate designs.

J-one operates through three coordinated locations: Tokyo handles client consultations and customer support; Kofu provides integrated production, including model making and casting; and Bangkok handles products that are difficult to manufacture in Japan. This network enables the company to respond flexibly to diverse client needs. J-one also offers product and technical proposals tailored to each brand's concept, presenting physical product examples to help clients explore new design possibilities beyond drawings alone.

The company places strong emphasis on training skilled artisans and passing on traditional manufacturing expertise to the next generation. From original jewelry development to OEM/ODM production, J-one is a manufacturing partner dedicated to helping jewelry brands enhance product quality and strengthen brand value.

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