Image by thomas pix via FlickrMuch of what happens musically in introductions revolves around using the dominant chord. This is sometimes referred to as the V chord (pronounced "five chord"). This chord varies according to what key you play the songs in. I will keep my examples in the key of C major because it is simple to understand. In the key of C the dominant chord is G7. I'll list the dominant chords for all the other keys later.
There are many variations on the basic dominant chord. Here are a few of the most common ones. You'll see them presented first in a straightforward theoretical way, and then you'll get a chance to learn them from a keyboard player's point of view. Most of the intro examples you'll see here are based on this dominant chord.
G7 = GBDF and GG/GBDF
Gaug7 = GBD#F
G9 = GBDFA
G7b9 = GBDFbA
G9 = Bm7(b5)/G and it looks like this: G/ BDFA
G7b9 = Bdim7/G looks like: G/BDFAb
Bdim7/G means right hand plays Bdim7 chord while left hand plays single (or double) G note in bass.
G seven flat-nine could be written as either G7b9 or G7-9.
* List of Dominant Chords around the Circle of Fourths:
KEY DOMINANT CHORD
You might want to check out Karen's teaching video to clear up some music points for a refresher course: Dominant and Playing By Ear
Definition: Dominant Chord
Thanks for stopping by.
I hope you enjoy your stay at LadyD Piano.