Anglo-American popular music—like most music in the world—is so firmly based on the anhemitonic pentatonic (or at least diatonic) scale that it’s intriguing to note how successful songs can be despite unobtrusively break the rules.
Putting familiarity aside, few listeners even pause to reflect that the remarkably similar chromatic opening phrases of these two melodies from 1939 and 1942 are highly implausible:
Hey, no-one’s ever going to listen to songs beginning like that—surely they could never catch on?! (For scathing reviews of Great Works, see Slonimsky’s Lexicon of musical invective.) Without context, you might suppose them to come from soundtracks for horror movies. OK, here’s a clue: like oxygen, it’s something to do with harmony (although no-one needs to know that)… Anyway, the composers soon realised that such slithery meanderings just weren’t going to work—but it was precisely those opening phrases that would become universal earworms. So here they are in context:
and (serving a similar role, for GIs spending their first Christmas away from home after entering the war) Bing Crosby with Irving Berlin’s I’m dreaming of a white Christmas * (“Dream on”—Greta Thunberg):
* With my ears attuned to Mahler, I can’t help hearing echoes of the motif in the third movement of the 9th symphony, which returns in the finale—its rhythmically related melody also opening on mi, but less chromatic: