into the material, rather than being part of a raised casting. Check these common locations: JustAnswer Under the seat cushion
Note: On very early chairs (1910s–1930s), serial numbers were sequential and do not contain the year. You must date these by Patent Dates and features.
If you cannot find the serial number, check these three common locations:
: The most frequent location, stamped on the underside of the wood or the metal seat frame. The iron base casting
| Source | What It Contains | Reliability | |--------|----------------|--------------| | (The Holy Black, Badger & Blade, Sharp Razor Palace) | Scattered user-reported serials with estimated decades | Moderate – good for narrowing to ±5 years | | Antique barber supply sites | General production eras (e.g., “1900–1915 oval base”) | Low precision, no serial matching | | eBay / LiveAuctioneers listings | Photos of serial plates from specific chairs | Useful for pattern recognition (prefix letters, digit length) | | Patent records | Dates of mechanisms (e.g., 1913 pump lift) | Helps confirm max age of a design, not a specific chair | | Official Koken records | None publicly available – company changed hands, old records lost | None |
