The bandoneon, which is sometimes called the button accordion, is a peculiar instrument–and I’m being charitable. A conventional accordion has that small piano-style keyboard for the right hand and a rack of chord buttons for the left. The bandoneon has no keyboard, and each of its buttons plays only a single note at a time; but since there are 76 buttons, the bandoneon has a range that nearly matches that of a piano. What makes the bandoneon “a diabolic invention,” in the words of Astor Piazzolla–its signal virtuoso, who has played the instrument for 60 years–is that each of its buttons actually plays two notes–one when the bellows are being closed, and another when they are being opened.

There’s more. “Ninety percent of what we play is opening the bandoneon,” Piazzolla explains, “because when you close it, it is harder to phrase it; it gives a different sound, and there is a lack of strength [to the tone].” But when it is fully opened, the bandoneon measures some seven feet across; consequently, during much of each performance, Piazzolla resembles a raptor of considerable wingspan about to enfold its prey.

The bandoneon was invented in Germany in 1854 as an inexpensive substitute for the harmonium (reed organ) for churches too poor to afford a decent keyboard instrument. During the next 75 years, they were manufactured only in Germany, culminating with the custom production of 25,000 instruments in 1930 for the Argentine market. (Production ceased as Germany went to war, and virtually no bandoneons–at least none of old-world quality–are produced today.)

The Argentines were not using their bandoneons in church, however. The instrument was actually introduced to Argentina in the late 19th century by Irish sailors, who played both the bandoneon and its cousin the concertina on ship; when they put into port, the sailors found a ready audience for the cheap and portable bandoneon among the working-class harbor dwellers. This rough-mannered demimonde, made up largely of Italian immigrants, was less concerned with the elevation of the soul than the relaxation of the flesh. And so the bandoneon went “from the church to the whorehouse,” as Piazzolla puts it–and to the waterfront dives and volatile cabarets of Buenos Aires.

In the 1880s, these immigrants had begun fusing their native musical traditions with the rhythms and passion of their new land. The bastard child that resulted was called tango. “I would say that 99 percent of the tango musicians were Italian immigrants,” explains Piazzolla, who is himself of pure Italian heritage; “that’s why it’s so sad, so dramatic.” As the Argentine-born music critic Fernando Gonzalez writes: “[Tango] grew up in the muddy fringes of Buenos Aires, in brothels, in a world of orilleros . . . men of fast knives and half-smoked cigarettes permanently dangling from a corner of their mouths.” When the bandoneon’s dark, lachrymose sound was brought to Argentina, the bastard tango had found its voice.

Astor Piazzolla heard that voice early; he recalls performing classical pieces (including church music) on the bandoneon when he was nine. Although he grew up in New York City, he was born in Argentina, in 1921, and he returned there when he was 17 to become a tanguero. But by the 1930s, tango had risen from its bastard status to become the national song of Argentina–a rigidly stylized, instantly recognizable form of music, played in elegant ballrooms as well as seedy nightclubs. Before leaving to form his own orchestra in 1944, Piazzolla worked with what was arguably the most important tango orchestra of the time.

But while Piazzolla, continued to hew the line as a tanguero, his interests and ambitions pointed elsewhere. He spent his nights leading the orchestra, but his daylight hours belonged to his classical-music studies with the Argentine composer Alberto Ginastera. In 1954, when he earned a scholarship to study with the famed composition teacher Nadia Boulanger in Paris, he was ready to abandon tango forever.

“I just wanted to be a classical composer,” he states. “I was against tango in all senses of the word. I didn’t like the life of tango; I was sick to death of cabarets and prostitutes and night living.” In Paris, he showed Boulanger all the music he had been composing “in a crazy way” for the previous ten years. “She analyzed all this music, and after two weeks she said, ‘This is very good music, very well written, but I can’t find you in it; there are parts of many composers, but no Astor Piazzolla.’ She investigated my private life, what I did, and I was very much ashamed to tell her that I was a nightclub musician. But she said she loved tango, and she even knew the instrument I played. Then she made me play a tango and said, ‘This is Astor Piazzolla. This is your music.’ She is the inventor of Astor Piazzolla.”

With Boulanger’s encouragement, Piazzolla began combining his ambitions with his experience, applying modern compositional and harmonic techniques to the tango. The pulsing rhythms remained, but he took liberties with tango’s fairly simple song forms, turning the tango into a still sensuous idiom capable of carrying serious compositional ideas. He returned to Buenos Aires, where instead of a small orchestra, he used a quintet; in contrast to the similar events taking place in neighboring Brazil, where the indigenous samba was being transformed into the jazzy and loosely arranged bossa nova, Piazzolla’s “new tango” was almost entirely written out. He made the tango flexible, pushing it to new levels of expression–thus earning the enmity of tangueros throughout his native land.

In fact, Piazzolla’s infamy as a revolutionary is exceeded only by his renown as a composer. The new tango, lauded in Europe and America, was no hit in Argentina, where most people resented Piazzolla’s experiments; he was accused of pretension, of cultural heresy, of trying to dress the old whore in society gowns. Tango fans reviled him, and older tango musicians, steadfast in their approach to the idiom, threatened him with beatings and worse; Piazzolla, who is combative and nonconciliatory by nature, did nothing to ease the tension (“I wasn’t strangled to death because I learned growing up on the streets of New York to defend myself”). Just last month, Piazzolla, says, an Argentine taxicab driver railed at him, calling him a communist when he recognized the master of new tango in his cab. Understandably, for most of the last three decades, Piazzolla has lived outside of Argentina.

Piazzolla has continued to grow as a composer, trying new forms and settings, such as the score of the 1987 stage show Tango Apasionado, a collaboration with jazz vibraphonist Gary Burton, and several concerto-length works. He has also recently formed a new band, a sextet that features a second bandoneon and cello. Piazzolla has been feverishly composing new music for this group, much of which will be heard at his concert next Thursday, May 18, at Park West, 322 W. Armitage. The show starts at 8 PM and tickets are $20; call 929-5959 for more information. The concert is presented in conjunction with WBEZ FM, and for what, it’s worth, I’ll be onstage too, acting as a nonpaid emcee for the evening. Full-disclosure regulations demand I tell you nothing less. Besides, as everyone knows, it takes two to tango. (Sorry.)