Every aspiring keyboardist will eventually be confronted with the challenge of accurately playing three notes in one hand against two in the other. This is otherwise known as a polyrhythm, the definition of which is two or more conflicting rhythms played simultaneously. While there are numerous possible polyrhythms, the most familiar is three notes played against two:
When first confronted by a rhythm like this, too many musicians will trust their eyes – and perhaps say a little prayer – to get it right, because after all the placement of the notes makes it obvious approximately where each note is to be played.
Unfortunately, trusting the eyes won’t necessarily lead to an accurate performance of this or another polyrhythm. Is there a better solution?
There is, and simple mathematics provides it. You can play three against two accurately by counting to the least common multiple of the two rhythms, which is six.
So in this example of eighth note triplets played against eighth notes, the solution, shown below, is to count sixteenth note triplets. (Of course, you first need to know how to accurately count triplets, but that can be learned by practicing with a metronome in which every note of a triplet receives one click.) The top staff shows the eighth note triplets (three per beat) to be played, the bottom staff shows regular eighth notes (three per beat) to be played, and the middle staff shows the counting. The arrows indicate how the notes correspond with the counting:
After you get the hang of it, turn on the metronome to keep track of the quarter note beat. Gradually increase the tempo while continuing to count out until it’s too difficult to get all the words in. By that time you should have the feel of it!