I read this today about the "Tristan chord", after being pointed there by something on TOP.
http://en.wikipedia.org/wiki/Tristan_chordI was intrigued to read that Sullivan used it in a recitative in HMS Pinafore so I tracked it down and I found it comes when Josephine enters in act two, just after her opening words of "the hours creep on apace".
But I think it's stretching things a bit to call it the Tristan chord there. In the treble stave of the vocal score, there are the notes F, A flat, B and E flat, so it's the same notes with A flat for G sharp and E flat for D sharp. But there's a G in the bass, rather as a pedal note, I think, and the E flat in Pinafore is more of a passing note and not really part of the chord. The chord in Pinafore resolves to C minor in the next bar.
I could be wrong, of course! But I don't think Sullivan had Tristan und Isolde in mind there.
