This 1963 Martin D-21has had one owner since it was purchased new in early 1964.

Martin made fewer than 3000 of these guitars during its original run between 1955 and 1969, so these are very rare. 
The design is basically a hybrid of the D-28 and the D-18. The back and sides are solid Brazilian rosewood like the 28. The fretboard and bridge are also Brazilian rosewood, while these parts are ebony on the 28. Appointments for the fret markers, rosette, and bindings are 18 style. 
The guitar had complete restoration work done at the Martin factory back in '97. They did some crack repairs, replaced the bridge and plate, did some finish work over the crack repairs, and refretted and reset the neck. This is why the guitar is in such stunning condition. Because all the work was done at Martin, none are depreciative.

 
Stan Jay of Mandolin Brothers wrote an appraisal for this guitar back in 2007, which is included with the guitar. Also included with the paperwork case candy are the original 1997 repair slip from Martin, a copy of the original Martin registration card, and a copy of the original sales receipt from 1964. 

Structurally, the guitar is in prime condition. No loose braces, open cracks, or bridge issues. Martin didn't use adjustable truss rods during this period but the neck is straight as an arrow. 

The action is on the high side of normal in the upper register, but very easy in the lower. Many bluegrass style players like the action the way it is, so I haven't performed another neck reset. Vintage Martins typically get 2 resets by the time they turn 60. If a buyer wants the action to have a more modern feel, I recommend consulting with a competent local luthier to reset the neck. I can also make arrangements with you to reset the neck myself. I've been a professional guitar tech for more that 25 years and was the last Head of Repair at Mandolin Brothers, so I'm more than qualified to do the work should you request it.

The guitar comes with a non-original hardshell case. I've factored in a 10% depreciation for the lack of the original. 
I believe the price is extraordinarily reasonable for a guitar like this. To find a true vintage, Brazilian rosewood guitar of this quality for less than $15k is more of a rarity than this guitar already is. 

Thanks for looking and feel free to ask any questions you may have.

All serious offers will be entertained.