I was reading this thread, and the (older one on the same subject. Then half an hour later I stumbled upon this weird Betty Boop cartoon on YouTube.
WARNING! You may find that cartoon offensive or just debased in a multitude of ways, and watching it may be a violation of copyright laws.
So I felt I had to get an account here to tell you about this.
The video is not dated on that page but elsewhere on the Internet it is said to be from 1935 or 1933.
The riff comes in at about 2/3 of the length of the video. At first it features in a slightly variated rhythm (here represented in a formalized version of the “dee-duh notation” (dee=1/8, duh=1/4, DUH=1/2)):
melody (C major/A minor): d-d-d-d-c-c-a-a-a-a-c-c
But later it comes in exactly the “modern”, “Kong-Fu Fighting” variant. i.e. when this (vaguely) chinese (i.e. “asiatic”) baby prodigy starts practising shooting on (european?) tin soldiers (thereby demonstrating the extent of the “yellow danger” of the growing asiatic hordes that are trained as soldiers already from the cradle (being scared only perhaps by a jack-in-the-box with a jewish nose). Or am I reading way too much into this cartoon?…), and at the same time that it’s combined with a trumpet fanfare for the militaristic connotation.
So, as user zut mentioned, the intro to the song Chinatown, My Chinatown from 1910 contains a similar theme. And it seems to me that it’s possible that it originated there.
But then there must have been another influential version (let’s call it the “theme Q”) somewhere inbetween 1910 and 1935 that established the “definitive modern form” of the theme, as it appears in the BB cartoon (It is obviously totally impossible that this cartoon was itself that influential).
It is of course also equally possible that even “Chinatown, My Chinatown” is only using an already established cliché.