Harmonization a minor third in a major key

Question

I have stumbled on a jazz song in key of major E which at one point has a minor third in the melody - tone G. It is at 0:15 in this YouTube video:

.

Time: 0:15 E ? F#m7 B7b9 Cdim7 E#dim7 |-- -- -- -- -- --|-- -- -- -- -- --|-- -- -- -- -- 0-|-- -- -- -- -- --| |-- -- -- -- -- --|-- -- -- 3- -- --|-- -- -- -- 2- --|1- -- 4- -- 7- --| |-- -- -- 1- -- --|-- -- -- 3- -- --|-- -- -- 2- -- --|2- -- 2- -- 5- --| |-- -- 2- -- -- --|-- -- 2- -- -- --|-- -- -- -- -- --|1- -- 4- -- 7- --| |-- -- -- -- -- --|-- -- -- -- -- --|-- -- -- -- -- --|2- -- 3- -- 6- --| |0- -- -- -- -- 4-|3- -- -- -- -- 0-|2- -- -- -- -- --|-- -- -- -- -- --| Od-chá- zím z domova a beru s sebou klíč Mož-

I wonder why does the 3x233X chord work. What led the composer to use it? How are usually m3 harmonized over the major scales? Is the G just passing tone to the ii (F#m)? The tones of the chord are G E Bb D. It could be understood as the 2nd inversion of C9, so C9 with the fifth in the bass. Or Em7b9 with the m3 in the bass.

Thanks for any comments :)

Have a great day, Marek

Answer 1

In isolation, that chord is a Gm6 (as pointed out in a comment by Tim), or an inversion of Em7(b5). However, neither of these two names explain the chord's function in the given context.

In my opinion, there is only one way to test a theoretical explanation of musical function: can you hear the chord function in the presumed way? When I asked myself which function I hear, then the answer was pretty clearly a V7/V, i.e., a secondary dominant leading to the V chord B7. In this case, as is very common in jazz, the V chord is preceded by its related ii chord (F#m7).

So how can a Gm6 / Em7(b5) chord function as a F#7 chord (which is the dominant of B7)? It can because it shares the same chord scale. I hear that chord functioning as an altered F#7 chord, and the F# altered scale is the 7th mode of the G melodic minor scale, the appropriate chord scale for Gm6. Also note that the chord contains the tritone E-A#(Bb), which characterizes the dominant F#7. The bass note G nicely approaches the F# of F#m7 from above, coming from the G# that is played just before.

This is in line with your observation that the chord is similar to a C9 chord, which would be the tritone substitution of F#7, generating an altered dominant sound leading to a chord with root B. If there were no F#m7 chord preceding the B7 chord, the bass note C would indeed have been a more obvious choice.

There are probably other ways to hear and explain that chord, and I'm looking forward to reading other plausible explanations.