Next to the Blues, "Rhythm Changes" is probably the most often quoted set of chord changes in Jazz. Rhythm Changes are based on the chord changes to "I've  Got Rhythm" by George Gershwin. Numerous jazz standards have been based on  these changes. The most famous of these are probably Sonny Rollins' "Oleo",  Thelonius Monk's "Rhythm-A-Ning" or "Anthropology" by Charlie Parker.  "Rhythm Changes" is a 32 bar song in an "AABA" form. In a 32 bar "AABA" form   the song is divided into four, 8 measure sections. The first 8 bars, the "A"  section is stated and then restated before moving to the "B" section or  "bridge" The final 8 measures of the tune is a restatement of the "A" section.  The final "A" section will usually contain a "turnaround" which leads back to  the top of the form. Since "Rhythm Changes" has been around for quite a while  and has been the basis for many jazz tunes for nearly 70 years, we can trace  the advancement in reharmonization techniques through different variations of  the song. I have presented two choruses of Rhythm Changes, in Bb. I have used  all the techniques previously discussed and added a few new reharmonizations  techniques, that I promised you. Since we've covered most of the basics, let's  dig right in.

  The "A" Section: Chorus 1, Measures 1-8

The first "A" section, measures 1-8, are the actual chords changes of the tune  without reharmonization. Except for the Eb- in measure 6, the piece is  diatonic (in the key) to Bb. The first 4 measures are two series of I-VI-II-V  chord progressions. Each chord gets 2 beats.The I-VI-II-V is one of the most  recognizable chord progressions. Measure 5 has a Bb leading to a Bb7, this is  actually the I chord (Bb) leading to the secondary dominant (Bb7) of the IV chord (EbMaj7). The Bb7 can also be called the "V7 of IV". The V7 of IV (Bb7)  logically resolves to the IV (Ebmaj7) in measure 6. The Eb-7 is a passing  chord to the Bb in measure 7. If you examine this progression Ebmaj7 (Eb, G,  Bb, D) to Eb-7 (Eb, Gb, Bb, Db) to Bb (Bb, D,F) more closely, you will see a  common tone, Bb, to all the chords. Additionally you will see chromatic voice  leading from G to Gb to F in one of the voices. Measure 7 and 8 repeat the  I-VI-II-V progresion. Rhythmically, I have played this as straight quarter  notes. I have done this to try to recreate the feel of a 1930's style rhythm  guitar part.

 Notation
 Real Audio File