Kay Uno

What Kay Uno does

Kay Uno (株式会社ケイ・ウノ, K.UNO) is a privately held Japanese custom jewelry manufacturer and retailer founded in 1981 and headquartered in Chikusa Ward, Nagoya. The company designs, manufactures, and sells bespoke engagement rings, wedding bands, fashion jewelry, watches, baby rings, and pet jewelry through more than 30 directly managed retail stores spanning Hokkaido to Okinawa, plus an owned e-commerce site. It is the largest custom-jewelry brand in Japan by store count, with a vertically integrated operating model that places approximately 150 in-house craftsmen at company workshops — most stores have an attached open workshop visible from the sales floor — supporting roughly 40,000 unique custom designs per year.

The technology stack centers on proprietary jewelry craft rather than software: an in-house 3D optical diamond analysis system (developed 2008) is used alongside the third-party Sarine Light™ grading system to certify the Premium Loving Heart Diamond standard at 110%+ brilliance versus average Excellent cuts, and the patented SweeTrick Diamond® cut (Patent No. 5486874, 2016) is a signature shape used exclusively under the Disney Design line. The product portfolio spans a main K.UNO Design collection and a Disney-licensed collection, with a separate U-TREASURE sub-brand (launched 2014) covering Pokémon and Sanrio character jewelry.

Commercially, K.UNO generates revenue primarily through one-time unit sales of custom and ready-made jewelry, with bridal pairs averaging around ¥200,000 and engagement rings starting near ¥120,000. Pricing is augmented by customization fees (engraving, stone addition, motif marks) and complemented by experiential services such as DIY handmade ring courses, propose ring packages with free 3-month redesigns, and loose-diamond gifting for proposals. Distribution is direct-to-consumer (own stores and e-commerce) supplemented by Zoom-based live video consultations, a web-based custom order intake, and a small set of partner-store placements in Shikoku and Tohoku where K.UNO has no directly managed presence. The customer base is overwhelmingly long-tail individual consumers (500,000+ served couples cumulatively), with bridal as the primary segment, followed by fashion, baby/maternity, pet, and occasional corporate/team commissions. The company is founder-controlled with no disclosed external investment and no public listing.

Name

Kay Uno

Legal name

株式会社ケイ・ウノ

Website

https://k-uno.co.jp

Company type

Private

Founded year

1981

Operating status

Operating

Headcount range

501–1,000 employees

Short description

Kay Uno is a privately held Japanese custom jewelry manufacturer and retailer, founded in 1981, operating 30+ directly managed stores nationwide. It serves primarily bridal customers with bespoke engagement and wedding rings produced by in-house craftsmen, alongside fashion, watch, baby, and pet jewelry lines.

Ownership category

akta.pro rank

Product category

Custom Jewelry / Bridal Jewelry

NAICS

Jewelry Retailers (458310)

SIC

Jewelry, Silverware & Plated Ware (3910), Retail-Jewelry Stores (5944)

akta.pro primary industry

Custom Bridal & Engagement Design (CRAKAHAB)

akta.pro secondary industries

Bridal & Engagement Jewelry Manufacturing (CRAKAIAC), Jewelry, Watches & Luxury Goods Marketplaces (CRAFABAK)

Keywords

• Custom jewelry manufacturing
• Engagement ring retail
• Bridal jewelry stores
• Bespoke jewelry design
• Wedding band sales

Headquarters

HQ city

Nagoya

HQ country

Japan

HQ region

Asia

Offices31 records

Markets served

GTM type

B2C

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Supply Chain, Marketing or Sales, Infrastructure, Technology or R&D

Revenue model

1. Custom Jewelry Sales (Bridal & Fashion): One-time purchase model for engagement rings, wedding bands, fashion jewelry, and watches. Products sold at set retail prices with customization/addition fees. Average bridal ring purchase is around ¥200,000 for a pair. Full-order custom pieces command premium pricing. Revenue is generated per transaction without recurring component.
2. DIY / Handmade Ring Course: Customers craft their own engagement or wedding rings at K.UNO's workshop stores. Separate fee for the handmade course experience. Minimum lead time of 2 weeks from consultation. Completion can be same-day depending on design complexity.
3. Propose Ring Package: A specialized engagement ring package (¥214,700 reference price for ring setting + diamond) allowing recipients to redesign the ring after the proposal. Design change within 3 months is free for designated designs.
4. Loose Diamond Sales (Diamond-only Purchase): Sale of loose diamonds (裸石/ルース) for propose purposes and later setting into jewelry. Premium diamonds such as Premium Loving Heart Diamond (from ¥316,800) and Two-as-one Diamond sets (from ¥372,900) are sold as loose stones.

Pricing tiers

Go-to-market motion2 records

Distribution channels6 records

Marketing channels7 records

Core offering

Kay Uno (K.UNO) is a vertically integrated Japanese jewelry manufacturer and retailer that designs, handcrafts, and sells custom-made bridal jewelry (engagement rings, wedding bands, set rings) along with fashion jewelry, watches, Disney-licensed designs, baby rings, pet jewelry, and accessories. The company runs 30+ directly managed retail showrooms across Japan and a D2C e-commerce channel, supported by approximately 150 in-house craftsmen producing up to 40,000 unique designs per year. Services include bespoke custom order, DIY ring-making courses, propose-ring redesign, diamond proposal, live Zoom consultation, and lifetime free after-sales service.

Product overview

Kay Uno is a Japanese bespoke jewelry brand operating over 30 directly-managed stores nationwide. The company offers a comprehensive portfolio centered on custom-made bridal jewelry (engagement rings, wedding rings, set rings) and fashion jewelry (rings, necklaces, earrings, bracelets), complemented by watches, baby rings, and pet jewelry. The brand operates two sub-lines: the main Kay Uno Design collection and the Disney Design collection featuring licensed Disney-themed pieces. Core services include custom design (full bespoke and arrange orders), DIY ring-making courses, a unique proposal ring service allowing post-proposal redesign, and loose diamond gifting for proposals. The company also provides online services including live video consultations via Zoom and web-based custom order processing. Manufacturing is conducted in-house at company workshops with approximately 150 craftsmen.

Differentiator

Problem solved

Functional benefit

Brands

• U-TREASURE: Character jewelry brand featuring Pokémon and Sanrio characters, launched in 2014

Products and services

• Engagement Rings (婚約指輪) Custom-made engagement rings in platinum 950, K18 gold (yellow, pink, white), and K14 rose gold, available as ready-made designs or full bespoke creation, targeted at couples planning marriage. Entry-level platinum 950 with center diamond starts from ¥120,000+; premium options include the proprietary Premium Loving Heart Diamond with 110%+ brilliance.
• Wedding Bands / Marriage Rings (結婚指輪) Wedding bands (his-and-hers pair) in platinum, K18 gold, K14 gold, and wood-grain metal patterns, available in simple or elaborate designs. Platinum 950 pair starts from ¥140,000+; average pair purchase is ~¥200,000. Engraving and customization fees apply additively.
• Set Rings (セットリング) Coordinated engagement and wedding ring pairings designed and crafted to be worn together as a matched bridal set, available across the K.UNO design range.
• Fashion Jewelry (ジュエリー) Non-bridal fashion jewelry including rings, necklaces, earrings, bracelets, eternity rings, charms, and other accessories in precious metals with diamonds and colored stones, available ready-made or via custom order for general consumer and commemorative-gift use.
• Watches (ウォッチ) — Liberore and CustoWa Ladies' Liberore watch collection and CustoWa custom mechanical watch line with personalization options for dials, bezels, hands, and engravings, used as bridal gifts and personal timepieces.
• Disney Design Jewelry Collection (ディズニーデザイン) Licensed Disney-themed jewelry (engagement rings, wedding bands, fashion jewelry, watches, and goods) featuring Disney characters, including the proprietary SweeTrick Diamond® Mickey Mouse silhouette cut, sold across all K.UNO channels.
• Baby Rings (ベビーリング) Commemorative rings for newborns and babies, often featuring birthstones and customizable designs, sold as gifts for parents and family members.
• Pet Jewelry (ペットジュエリー) Custom jewelry featuring pet motifs — pet portraits, likeness charms, and memorial pieces — commissioned through in-store or online consultation for pet owners.
• U-TREASURE Character Jewelry Brand Sub-brand of Kay Uno launched in 2014 for character-branded jewelry featuring Pokémon and Sanrio characters, including bridal pieces, available at select K.UNO stores.
• DIY Handmade Ring Course (手作りコース) Workshop experience where customers handcraft their own engagement or wedding rings under craftsman guidance at designated K.UNO stores; reservation required.
• Propose Ring Package (プロポーズリング) Specialized engagement ring package priced at ¥214,700 reference that allows recipients to redesign the ring after the proposal; free design change within 3 months for designated designs.
• Diamond Proposal Service (ダイヤモンドでプロポーズ) Loose diamond (88f8/ルース) gifting for proposal purposes, later set into the recipient's preferred jewelry design; Premium Loving Heart Diamond from ¥316,800; Two-as-one set from ¥372,900.
• Live Zoom Consultation (ライブ接客) Real-time video consultation service (live customer support) using Zoom for design proposals, jewelry selection, and order processing for remote customers who cannot visit a showroom.
• Web-based Custom Order (ネットでオーダーメイド) Online form-based custom order service enabling customers to submit requirements and receive design proposals through a dedicated messaging platform without an in-store visit.
• Goods and Accessories (グッズ) Accessories including baby spoons, forks, cufflinks, tie bars, and jewelry cases, sold alongside K.UNO's jewelry collections.

Quantifiable outcome

• 500,000+ couples served over the brand's history
• +4 more outcomes

Named customers4 records

Segments5 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Five partnerships are on record, tiered minor and core.

• U-TREASUREminorOEM/ Whitelabel/ Licensing PartnerU-TREASURE is a character jewelry sub-brand launched by K.UNO in 2014, specializing in Pokémon and Sanrio Characters (Hello Kitty, etc.) branded jewelry. Available at select K.UNO stores. Handled as a separate branded line from the main K.UNO and Disney brands.
• hirai art gallery (ヒライアートギャラリー)minorChannel Partner/ Reseller/ DistributorLocated in Matsuyama, Ehime Prefecture. A jewelry select shop carrying 45 brands and 1,500 items. K.UNO products are featured as part of their curated collection, expanding K.UNO's reach to Shikoku where K.UNO has no stores.
• KAMODA (小田塚宝石店)minorChannel Partner/ Reseller/ DistributorLocated in Yamagata Prefecture. Handmade/custom jewelry experience and full-order shop. K.UNO products are displayed at their location, serving customers in the Tohoku region.
• BROOCH (ブローチ)minorChannel Partner/ Reseller/ DistributorLocated in Niigata Prefecture. One of the largest jewelry department stores in Niigata by brand count. K.UNO jewelry is featured among their brand selection.
• Sarine Technologies (サリン・テクノロジーズ)coreTechnology or IntegrationK.UNO uses Sarine Light™ (サリネ・ライト™), an international third-party diamond grading and certification system by Israeli company Sarine Technologies, for evaluating and certifying diamond brilliance. Diamonds achieving the highest 'Ultimate★★★' grade are distinguished through this system. K.UNO has been using Sarine grading since 2017.

Scale indicators5 records

Recent moves7 records

Expansion highlights6 records

Market position

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/Kuno_PR
• YouTubeyoutube.com/c/KunoOfficial
• Facebookfacebook.com/KunoOfficial
• Instagraminstagram.com/k.uno_official/?hl=ja

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Kay Uno