1931 C.F. Martin & Co. D-28

Authenticating a 1931 D-28 requires museum-level scrutiny, as only 22 were produced in this inaugural dreadnought year. Serial numbers for 1931 Martins fall in the 49,000-52,500 range — cross-reference with Martin's detailed sequential records maintained in Nazareth, Pennsylvania. The bracing must be scalloped X-pattern with Adirondack spruce braces joined with hide glue; use a mirror and light through the soundhole to verify the scalloped profile where the braces taper to thin edges. The top is Adirondack (red) spruce, which shows wider, more irregular grain than the Sitka spruce used in later decades. Back and sides must be Brazilian rosewood — look for the characteristic dark chocolate-to-purple coloration with dramatic figure and an almost oily appearance, distinct from Indian rosewood's lighter brown and straighter grain. The herringbone purfling around the top should be inlaid wood strips in a zigzag pattern, not a printed or painted imitation. Binding is grained ivoroid with the herringbone running beneath it. The neck is a chunky V-profile mahogany with no volute — the headstock transitions smoothly into the neck. The ebony fingerboard should show dot inlays at positions 5, 7, 9, 12, and 15, with the 12th fret having two dots. Tuners are open-back Grover Sta-Tite with butterbean knobs. Inside the body, look for the Martin stamp on the neck block and the paper label — 1931 labels feature the old-style Martin & Co. logo with the Nazareth, PA address. Red flags include any polyurethane finish (should be nitrocellulose lacquer showing fine checking), a replaced belly bridge with different pin spacing, evidence of a neck reset with modern epoxy, or non-scalloped bracing. What sets 1931 apart from 1933-1935 is the extremely low production number and slightly different neck block shape as Martin refined the dreadnought design in its first year.