Black Walnut is a dense and stiff tonewood that often shows beautiful figuring. Like Koa, Walnut yields bright treble notes, but it has a more present midrange that splits the difference between rosewood and mahogany. Walnut also starts off a little deeper on the low end, initially giving it a slightly woodier sound than Koa. The low end will continue to fill out after it's played in over the years.

This 12-Fret 0 was custom-made with solid Black Walnut top, back, and sides. It is a subtle nod to the 12-fret single-0s Martin made entirely out of Koa in the '20s. The Black Walnut shows incredible book-matching on the top and back, and that demonstrates that this guitar was carefully constructed with top-level tonewoods. 

From there, it is set up with understated Style-17 appointments, an Ebony belly bridge, and an Ebony fingerboard. While most 12-frets have slotted headstocks, this one doesn't, and that makes it so much easier to restring and adjust down the road. It also provides a touch of dustbowl-era elegance with the old-style Martin decal. 

Soundwise, this 12-fret produces shimmering bell-like trebles, and it has a strong mid-range and tight bass presence to balance out the sound. Like some 17-Series models, this Custom 0 has simpler, lightweight bracing, and that opens up the response for fingerstyle playing. Nevertheless, the stiff top can still handle a flat-pick. Overall, the versatility and balance of sound are impressive, and the subtle character of Black Walnut gives this custom Martin its own unique vibe. 

• Body: 0-12 Fret
• Top: Black Walnut
• Back & Sides: Black Walnut
• Neck: Mahogany
• Scale Length: 25.4
• Top Braces: Sitka/Non-scalloped 1/4"
• Top Binding: Antique White Boltaron
• Rosette: Single Ring, Thin B/M/B/M/B
• Neck Shape: Modified Low Oval w/ Performing Artist Taper
• Nut: Bone, 1-3/4" 
• Fingerboard: Ebony w/ Short-Pattern Diamond & Squares inlay
• Bridge: Ebony Modern Belly w/ Drop-in saddle
• Saddle: Compensated Bone, 2-5/32" spacing
• Finish Type: Satin
• Tuning Machines: Golden Age Relic Brass

This 2020 Martin Custom 0-17 is in excellent condition, showing only minimal signs of play and use (see photos). It is set up with low action and .012-gauge strings. The Black Walnut has a beautiful smell to it, also. This might be a weird thing to say, but this Custom 0 12-fret may be the best-smelling guitar in the shop. Seriously. It's an olfactory experience. It includes a Martin 500-Series hardshell case.