# What's going on functionally/structurally in these four bars of Rachmaninoff's 3rd piano concerto?

From Rachmaninoff's 3rd piano concerto 1st movement 2nd subject:

I've been trying to understand what's going on structurally in this passage but I'm having trouble figuring out what's going on. In the picture I've presented my chord analysis. In particular I don't understand what he's doing in the red section of the image. What I'm thinking is he's just treating D as borrowed "extension" of I(63) and then walking down to ii and then slowly back to V? Can anyone help me understand what's going on here?

I analyze this, broadly, as

```I | V/ii | ii | V
```

In more detail:

```m1: I        I[6-4]           I(over CPT*)            ii∅[4-3]/(V/ii)(from G minor)

m2: V/(V/ii) c.t.○(over PT)** V[6-5]/ii               V7/ii

m3: ii       V7/(V/ii)        VI7/(V/ii) = ii[6-5]*** V/V

m4: c.t.○7   V                ii[4-3]                 V[6-5]
```

*: CPT = chromatic passing tone

**: c.t.o = "common-tone diminished chord": see: A chord progression from Leavitt: how to analyze it correctly

***: This serves as a pivot chord. It forms a deceptive cadence in G minor but also serves as a pre-dominant `ii` chord in Bb major. The `C` is not accounted for directly in the deceptive cadence (`Eb`) chord, but is explained by the presence of `C` as a pedal tone throughout the measure.

• Please could you explain such notation as V/ii? (I see e.g. G/B as meaning a chord of G with B in the bass, but you seem to be using / in some other way.) Nov 20, 2020 at 7:04
• V/ii means the V chord in the ii key - so a secondary dominant leading to (a very temporary) c minor Nov 20, 2020 at 7:12
• @RosieF In addition to Alexander Woo's comment, you can read about "secondary dominants" in What is a secondary dominant chord? Nov 20, 2020 at 8:04
• @AlexanderWoo Thanks -- I know what secondary dominants are, but am used to the notation "V of ii" (and iv of vi etc.; the chord needn't be the temp key's V). Nov 20, 2020 at 9:56
• @Aaron: So how is one to understand "V7/(V/ii)"? The V7 as a secondary dominant of the secondary dominant of ii? So in this case the ii of B♭ major is a C minor triad, and its secondary dominant thus a G major triad, whose secondary dominant would be a D major chord, D7 in this case. That checks out I guess. On a separate note, how come in measure 3 it moves from ii to V7/(V/ii) and right back to ii[6-5]? I would think there's a need to first resolve it to V/ii like at the end of measure 2 (with the V7/ii). Oct 30, 2023 at 22:47