Pizzicato is the plucking of any stringed instrument (especially any stringed instrument that is usually played with a bow, such as the violin). This is probably the most important sound that tango aficionados start recognizing and understanding. Sometimes the pizzicato part can be danced (see the example below), but it is often a sprinkling of glitter in the air. So please watch carefully as Troilo's orchestra plays "Quejas de Bandoneón." You may click here to go directly to Troilo's solo and the start of the pizzicati (passage of pizzicato) in the background, but I highly suggest that you watch the whole video clip, especially before and during Troilo's moving solo. Notice the violinists playing the pizzicati standing behind him. Tangueras/Tangueos, please note: One can dance the pizzicati! I think I would dance the melody in this example. Often dancers, even professionals, trudge along on the pulse in spite of the melody and the pizzicati. However, if you have a playful partner with good reflexes and a good ear, try listening to the "queja" (complaint) rather than being the complainer. The "listeners" are the violinists, playing the pizzicati saying, "¡No me digas!" as Troilo complains of lost love. Then you and all of Troilo's friends can gather around him later in sympathy with the sweeping bowed passages after the solo. An example of dancing the pizzicati follows, but watch this first!
I also highly suggest you view a wonderful demonstration of pizzicato at this link,which will allow you to better understand why pizzicati can almost sound as if a banjo is in the orchestra.
Now here is the best part for dancers: How do you really dance the pizzicati (plucked passages)? Listen carefully to the video clip for the pizzicati, but please notice that these dancers to not always dance every fast passage or pizzicati! A beautiful melody often has the pizzicati sprinkling glitter in the background; so dance the melody or pulse! Pay attention to the many pizzicati and one of the clearest passages at about the 70-second mark, which Horacio Godoy and Magdalena Gutierrez playfully dance with little-bitty steps.
The king of pizzicato in tango
Who in the orchestra is most often in pizzicato? In tango the violinists are often playing pizzicato, but the bass is king of pizzicato, although the bassist uses the bow often. But the bassist tends to be a mischievous band member (since the drummer usually has this role); so the bassist in tango is known for even using the wooden back of the bow for percussive effects. Naughty! Let's not leave out the one instrument in a tango orchestra that has more strings than anyone else (230 strings on the average piano). Rarely does one see the pianists plucking their instruments, and they tend not to be mischievous like bassists! However, some pianists (especially when drunk) are known to get up and pluck their instrument. See the pizzicati (pizzicato passage) by the Piano Guys below for a good example of how even the piano can be played pizzicato.
Note that the above piano is being played in three major musical categories: A keyboard instrument, a percussion instrument (struck with hands and hammers) and a bowed string instrument.
No, don't order a pizza... pluck your strings!
Here is an example of 4 musicians playing tango with bows (arco) and pizzacatto (pizz). The cello is the bottom line and is already playing pizzicato, others are starting or stopping the pizzicati. The top two lines are violins and the second line from the bottom is the viola.
Obscure but interesting information you'll need before going to a Baroque cocktail party: Plucking can be done artificially. Technically speaking, the harpsichord is a "plucked" instrument because the strings are plucked by a quill after the harpsichordist strikes the key. The piano is considered a percussion instrument because the hammers hit the string. Of course, both are played exactly the same through a keyboard. While doing the same thing (playing the keyboard), the keyboardist can be a "plucker" or a "percussionist." But I wouldn't make these accusations to a harpsichordist in public. :-)
Photo credit of woman plucking her A string: http://violinfromscratch.com/learn-violin/holding-the-violin-and-playing-pizzicato
After I posted the above blog, I found a better quality video clip of Troilo that I will add if time allows: http://youtu.be/y32Gn-Z4DFk