Paul Familetti, Wikimedia Commons // CC BY 2.0

From his gigs at Tootsie’s Orchid Lounge and the Grand Ole Opry to his membership in the Highwaymen, the name “Willie Nelson” is almost synonymous with country music.

So what’s he doing playing a Martin N-20 classical guitar?

In 1969, Nelson played a Baldwin acoustic. He laid it on the floor of the stage while playing a gig one night, and, in his words, “a drunk stepped on it.” He sent the battered remains to music legend and guitar designer Shot Jackson to see if he could repair it, but the guitar was beyond saving. At least, most of it was. Jackson mentioned that he could probably save the Baldwin’s pickup, which Nelson favored because it gave him a much bigger sound onstage. Nelson needed something to play, so Jackson offered him a Martin classical guitar that he happened to have hanging out in the shop. For the low price of $750, Nelson agreed—and the most famous artist-guitar duo in the history of music (arguably) was united.

Because classical guitars are meant to be fingerpicked, not strummed, they don’t typically come with pickguards, the piece of plastic that protects the wood of the body from the constant wear and tear of playing. Nelson’s Martin was no exception—and that’s why a large hole has formed in the guitar over the decades. But the hole doesn’t bother Willie. In fact, he thinks it improves the sound, and Martin guitar designer Dick Boak agrees: “As you scratch away at the top, the diminished thickness of the membrane will most likely make the guitar sound better.”

Nelson is so attached to the guitar that he eventually gave it a name: Trigger, after Roy Rogers’ horse. During his infamous tax problems in the 1990s, Nelson had Trigger hidden away with his daughter to make sure that his most valuable asset wouldn’t be seized along with the rest of his property. Obviously, the guitar survived the raid—but if Trigger finally reports to that big tour bus in the sky, don’t be surprised if Willie retires. He has long said that he’ll quit playing when his guitar does, though he doesn’t believe that will happen, saying, “probably Trigger will outlast me.”