Martin began offering a sunburst finish on some flat-top guitars in 1931. Sunburst refers to a dark outer edge with a gradual fade to light in the center of the guitar. Martin aficionados usually refer to this as a “shade top.” Shade top Martin guitars from the 1930s are highly collectible because of their rarity and aesthetic beauty. Full production numbers aren’t available since not all shade top finishes are recorded as such in the Martin production archives. Records exist of only 12 0-18 models with shaded finish from 1937, but we know there were at least 13 made since this one is not recorded as shade top.
The unmistakable original wear on the pickguard is a good way to evaluate an original shaded finish. Since the sunburst finish is considered more valuable, many are inclined to refinish a Martin guitar as a shade top instead of its original natural finish. It’s difficult to match the wear from an original Martin shaded finish so it’s one way to distinguish and original from a refinished guitar.