Blues in the Jazz Harmony Lab

The Jazz Harmony Lab is a free piano practice tool by Jason Zac at Nathaniel School of Music in Bangalore. Use it if you already know seventh chords and want to practise ii–V–I at the piano, with real sound, not on a worksheet.

Open Shells and leave the key on G. The lab spells the major ii–V–I as Am7, D7 and Gmaj7. Those three chords share guide tones: C and G on Am7, F# and C on D7, B and F# on Gmaj7. One voice stays; the other moves a semitone. Press Play and watch that connection on the rails.

The same page then grows the two-note shell: invert it (3–7 and 7–3), hang one colour on it, split it across two hands, spread it in the left hand as 1–7–3, put a plain seventh chord over the root for m9, m11, major 9 and 6/9, or open it into a rootless A/B grip. Other modes take the same grammar into the dominant circle, turnarounds, jazz blues, a standards workshop, and a voicing palette. Share sends the exact key, voicing and tempo.

How to use it

  1. Stay on Shells. The default key is G.
  2. Press Play (or Space) and watch Am7, D7 and Gmaj7 go by on the rails.
  3. Switch First shape between 3–7 and 7–3 without stopping the pulse.
  4. When one key is automatic, set Route to Circle of 5ths for all twelve keys.
  5. Use Share in the lab to send that exact setting. Hash links from older lessons still open on the matching mode.

Questions people type

How do I practise ii V I on piano?
Open the Jazz Harmony Lab on Shells, leave the key on G, and press Play. Loop that cadence slowly and follow one guide-tone rail with your voice. Then switch First shape between 3–7 and 7–3 without stopping. When one key is automatic, set Route to Circle of 5ths.
What are the ii V I chords in G major?
Am7, D7 and Gmaj7. That is how this lab spells the major ii–V–I in G: ii is A minor 7, V is D7, I is G major 7.
How do guide tones connect jazz chords?
The 3rd and the 7th are the two-note shell. In a G-major ii–V–I, C is common from Am7 to D7 while G moves to F#. Then F# stays from D7 to Gmaj7 while C moves to B. One voice holds; the other moves a semitone.
How can I practise ii V I in all keys?
Set Route to Circle of 5ths for all twelve keys, or use either whole-tone family. The lab keeps the same voicing and transposes the cadence.
How do I move from shell voicings to fuller jazz piano chords?
Keep the two guide tones where they are and add one note from the Shell Library, or step the Voicing control from shell to colour shell, split shell, then rootless A/B. The hand does not learn a new shape — it hangs one extra note on the same shell.
Is the Jazz Harmony Lab a piano course?
No. It is a free practice lab. For the theory of the V7 chord, review dominant seventh chords. To learn this material in class, explore intermediate piano lessons or explore free music lessons at Nathaniel School of Music.

Learn this properly

The strip above the lab is the school path: paid piano training, free lessons, WhatsApp. This page is the practice desk. When a voicing needs the V7 explained, review dominant seventh chords. For spread shapes and extensions on every chord, open the companion app, the Voicing Room. When you want the same harmony taught in class, explore intermediate piano lessons or explore free music lessons.