I have been to a lot of concerts in my life and seen musicians playing a great variety of instruments in many different genres. I’ve also visited several museums of musical instruments, where I’ve seen such oddities as a guitar with both strings and a keyboard build into it.

But until a few days ago, I didn’t know there was such a thing as a bandoneon.

I saw and heard it being played during a recent performance by the St. Louis Symphony conducted by Leonard Slatkin. As it was building towards a magnificent finale of George Gershwin’s “An American In Paris,” we were also treated to pieces of Bertolt Brecht’s “Threepenny Opera” (whence came “Mack The Knife,” long before Bobby Darin turned it into a pop hit). Before that began, during the intermission, I looked at the SLSO’s printed concert program, which offers details on the composers, the soloists, and the instruments played in each piece. When I saw bandoneon listed for the Brecht segment, I asked my wife and the couple we were with if they’d ever heard of it. None of them had.

When the musicians returned, there was a woman sitting at the front of the orchestra, holding what looked like an accordion or concertina (or for fans of The Who, a squeeze box). That had to be the bandoneon. It wasn’t particularly well amplified, but I could hear a distinct reed-like sound emanating from it. As she played, the woman had an ear-to-ear grin, a rarity among symphony performers. Even when they’re getting a standing ovation, I don’t often see many of them smile.

When the concert was over, we were on our way out when I encountered the bandoneonist (yes, that’s what they’re called) in the lobby. I asked a few questions about the instrument, and she was more than happy to tell me about it. For instance, there were double reeds throughout that provide the tone. Modern bandoneons like hers multiple keys on each side to be played depending on whether she was pulling the bellows apart or squeezing them together, and since they are arranged differently on the right and left, she had to learn four entirely different layouts. She said that she’s normally a pianist, but had learned the bandoneon several years ago and loved it. After a few minutes, I thanked her and complimented her playing. She returned the thanks and we parted ways.

Later, I learned her name is Winnie Cheung, and — in addition to working with the SLSO — she plays with tango ensembles all around the world. So you’ll know what she and the instrument look like, here’s a one-minute clip of her playing the bandoneon at an event in Buenos Aires, Argentina, last year…