So, see, I was reading the post about the blog on memorizing tunes,
and the blog referenced several tunes that are embarrassing not to
know, and of course, I didn't know them... so, embarrassed, I
looked 'em up on the biab groups archive (thanks to whomever, great
resource), and lo, there be a tune called Impressions (among the must-
know list) and it's a cool tune with a mess of Dm's and a couple of
Ebm's... BUT ... and this is the kind of thing that makes me nuts...
the key is in C. There's no C chord in the whole chart. Not one. I
checked. Twice. No C.

So why is this not in the key of Dm?