The Cross Town Twelve Bar Blues
This is the simplest way to play a Twelve Bar Chord Structure in the key of G. Play it over and over, as per the repeat sign at the end of the entire twelve measures, until you can change chords at the correct time without looking at the notation.
The partial chord 45i has been used for the D chord. It sounds crisper than the 345i. You may find it worthwhile to practice the jump from the 123i to the 45i for a moment, before playing the entire piece.
Remember that one measure equals four beats, so that the term Twelve Bar refers to the length of one verse of this structure, as you can clearly see below. Instead of only indicating where the chords change, as has been done with the other songs in the book, in this piece the chord used in each measure has been indicated. This will help you to relate this piece to the chart on page 44, measure by measure. Notice the three beat turnaround, which includes two beats of D chord and one silent beat.
Other Harmonica Positions: First And Third
It is possible, although not as easy, to play blues on a C harmonica in keys other than G. Less convenient and popular but still common is the playing of C blues on a C harmonica. This is known as playing in "First Position", or "Straight Harp".
The least usual way to play blues that is still commonly heard is to play D blues on a C harmonica. This is known as playing in "Third Position". It is also occasionally referred to as "slant harp", and probably accounts for less than five percent of all blues played.
Although further discussion of either of these enjoyable and challenging ways of playing blues harmonica is beyond the scope of this book, they are covered in more detail in Progressive Blues Harmonica.
Rather than playing the three notes of each chord together, as above, in the following Twelve Bar Structure each note of the chord is played separately. Playing a chord in this way is known as "arpeggiating" a chord. This verse also features a full four beats of turnaround (including the final silent beat). By now, you should be working seriously on your ability to obtain single notes, if you cannot already do so.
A boogie woogie is a particular type of Twelve Bar structure. Originally based on the notes played by the left hand of New Orleans style piano players in the early part of last century, it has been adapted into a standard harmonica piece.
It is more difficult to recognize the Twelve Bar Structure in the boogie woogie than in the previous blues pieces, but a careful count of the beats will prove that the chord changes are less obvious but do occur in the correct places. Be prepared for the turnaround, which requires a jump from 6e to 1i.
