About Improvisation
Under each song and rhythm pattern are printed the letter names of the chords that can be used to accompany that piece. These particular chords are used because the notes of the song or the rhythm pattern fit in well with the notes of the chord.
When a harmonica player is playing a particular song, especially one that he or she knows well, the notes of the song are of primary importance, for it is the specific arrangement of the notes that makes a song recognizable. Although playing along to a chord accompaniment may make for a richer, fuller sound, it is not necessary.
Some types of music are not so much based on a specific arrangement of notes (which is called a melody, or tune). Instead, styles of music such as blues, jazz, and rock are often "improvised".
Improvisation is the act of creating music as it is being played. Unlike playing a specific song with its specified notes, this way of playing offers the musician a great deal of freedom in choosing the notes. However, the notes used in improvisation are far from randomly chosen. Improvisation will be covered, not in this book, but in Progressive Blues Harmonica, since it is in blues, rock, and jazz music that improvisation plays an essential part.
In order to give themselves a certain degree of order or organization, improvising musicians often play along with an accompaniment of chords. Thus they have a structure upon which to base their improvisations, and often allow their choice of notes to be determined by their knowledge of which notes will fit in well with those chords.
About the Twelve Bar Chord Structure
Most blues, many rock, and some jazz styles of music are heavily based on a particular repeated series of chords called "The Twelve Bar Chord Structure".
Literally thousands of well known blues, rock, and jazz songs use just this one structure, also known as the Twelve Bar Progression or the Twelve Bar Blues Structure, which you will play in a moment.
Note: a measure is often called a "bar", hence the term "The Twelve Bar Chord Structure" or "Twelve Bar Blues".
Playing A Twelve Bar Chord Structure In G On the C Harmonica
As discussed in Lesson Five, it is easiest to play a Major Scale in the key of C, that is, a C Major Scale, on the C harmonica, although Major Scales in other keys may be played once bending is mastered.
Similarly, it is easiest to play blues on the C harmonica in the key of G, although other key blues are possible for the advanced player. Playing in the key of G on a C harmonica is known as playing "second position" harmonica, or "cross harp". The chart below describes the how the G chord, C chord, and D chord are used to play a Twelve Bar Chord Structure in the key of G. Each "measure", or four beat segment, is separated by a "bar line".
Notice that four beats of D chord are played at the end of the verse. These final beats of D chord are known as the "turnaround", for they are used in order to indicate that a verse is about to come to an end, and the next verse is about to begin. The turnaround may be only two or three beats of D instead of four, or it may be omitted entirely. If the (D) turnaround is less than four beats long, G chord beats will replace the "missing" D beats, so that the entire verse remains 48 beats, or 12 measures, long.
In Lesson Thirteen, an entire twelve bar blues structure of this type will be presented, as well as two more exciting variations on the twelve bar blues.
