andi

At one point in my life I needed to know this for a test and I regret to inform you that as soon as that test was done, that knowledge left my brain. Both genres are “jazz that partnered with other genres, particularly R&B”

It’s maybe a timing thing? I want to say Hard Bop starting being a genre label in the 1950s and Jazz Fusion was a genre label in the 60s? Hard Bop came out of Bebop, which was blisteringly fast, so I’d also expect Hard Bop tempos to hang out around the 200 bpm range, and Jazz Fusion to have more variation there.

fusion is if you mix jazz and rock. hard bop is if you make jazz that kinda rocks. hope this helps. oh, it didn't? they're indeed quite different

hard bop is just normal jazz music except w/ an emphasis on rhythm and usually using some simpler melodies, drawing on all the parts of the tradition that also spawned rock n roll (blues, r&b, gospel). because rock n roll was more of a departure towards pure intensity, it made sense for jazzists to just mainline the stuff and that's when you get fusion.