Artist's commentary
Hang in There, Kogasa-san 1726
This trivia was worth about 16 'Wow's' to me. :-)
So far as it goes, I hear there's also pineapple bean paste, but it's all pretty much winter melon, or a half-and-half of winter melon and pineapple, it seems.
So long's it's tasty, ain't no big deal!
There's no nightingale in uguisu bean jam, either, is there! It's actually so named because it's the same greenish-brown color as a Japanese nightingale/uguisu.