| Böker — the stamps per the Zalesky chart (1837 → the present day) | 1837 → the present day (the chart up to G20/US5/R2; the Plus/Magnum/Manufaktur lines from 1990/2000) | 19 | This is the most worked-out layer of all straight razors: the chart prints 28 grouped stamps with years (plus the lines). The layer was carried over f |
| Country mark (lower bound, NOT a year) | the requirement applies from 1 March 1891 (Tariff Act of 1890, also known as the McKinley Tariff) | 2 | A country mark is only a LOWER BOUND (the item is no earlier than the introduction of the marking) and never a year. For Böker the mark GERMANY on the |
| Grind, spine, scales, etching — era markers of a straight razor | 1700s → mid-1900s | 16 | Shared layer for all straight razors: it does not date precisely, but it cuts off an era. All rows are printed wordings from a shop-page guide review |