Derived from Martin's 16" archtop guitars of the early 1940s. One with a wrecked top was retopped with a flattop by Marc Silber and Mario Martello, which influenced Matt Umanov to do the same for David Bromberg. The exposure through Bromberg influenced Martin to create a new, very successful series, the M-36 and M-38. These were essentially larger OMs, with the same narrow (4") depth. Several years later, Martin created their Jumbo model by increasing its depth to that of the dreadnaught.
This model is Martin's first Jumbo, with "45" style pearl hexagons and binding on the fretboard. Excellent condition except for a crack near the center seam below bridge, repaired to invisibility. It's got a deep, throaty tone - a fantastic rhythm guitar!