| Layer | Technology | Consumer Action | |-------|------------|------------------| | 1 | Public serial + captcha lookup | Enter code → receive “first seen date” | | 2 | QR code with unique token | Scan → shows production timestamp | | 3 | Blockchain registration (Ethereum/NFT) | Immutable proof of ownership | | 4 | Tamper-evident holographic seal | Visual + tactile check |

Despite serial number implementation, counterfeiters replicate valid codes, and Yonex does not offer a public online verification database (unlike brands such as Nike or Apple). Consumers rely on third-party forums or physical inspection guides.

| Product Type | Serial Location | Format Example | Notes | |--------------|----------------|----------------|-------| | Badminton racquet | Shaft cone (under grip) or cap | 250672JP | 6 digits + country code (JP, TW, UK, etc.) | | Tennis racquet | Butt cap hologram | Alphanumeric, 7-8 chars | Laser-etched under “Yonex” logo | | Strings | Packaging barcode | 12-digit numeric | Batch code, not unique per pack |

Author: [Your Name/Institution] Date: [Current Date] Abstract The global badminton and tennis equipment market is inundated with counterfeit products, with Yonex—a leading Japanese sports equipment manufacturer—being a primary target. Yonex embeds serial numbers on most genuine racquets and accessories as a primary anti-counterfeiting measure. However, the effectiveness of serial number verification remains contested due to inconsistent database access, replication of codes by counterfeiters, and a lack of public-facing authentication tools. This paper examines the structure, intended function, and limitations of Yonex’s serial number system. It then evaluates alternative verification methods (holograms, laser engraving, Sunken Logo technology) and proposes a multi-layered authentication framework. Findings indicate that serial number verification alone is insufficient; consumers must combine it with physical inspection and authorized dealer sourcing. 1. Introduction Yonex Co., Ltd. (founded 1946) commands a premium position in badminton, tennis, and golf equipment. Its flagship racquets—such as the Nanflare, Astrox (badminton), and EZONE (tennis)—retail for $150–$300+. This price point has attracted sophisticated counterfeiting operations. In response, Yonex introduced serial numbers on shaft cones, cap grommets, or hologram stickers.