A big source of confusion surrounding the meaning of hard bop is its geographical relationship with cool jazz, or, as it was often called in the 1950s, West Coast jazz. Many critics placed geographical labels on cool jazz and hard bop which were not entirely accurate. Many of the luminaries of cool jazz, including Chet Baker and Dave Brubeck, were based in Los Angeles. Thus, the term "West Coast Jazz" was born. And since hard bop arose as a reaction to cool jazz, and since most of its practitioners, like Miles Davis, Horace Silver, and Art Blakey, were based in New York, some critics decided to refer to hard bop as "East Coast Jazz."
But as Ted Gioia showed in his book West Coast Jazz: Modern Jazz in California 1945-1960, the linkage between cool jazz and the West Coast was tenuous at best. While many stars of cool jazz were based out west, some, like Gerry Mulligan and Stan Getz, operated out of New York. Conversely, many black musicians who would play an important role in hard bop, including Charles Mingus and Art Farmer, originally started out on the West Coast. "West Coast Jazz" was a convenient geographical association for cool jazz, but in reality, it distorted more than it illuminated.
Similarly, another source of confusion when it comes to the definitions of cool jazz and hard bop is the association between a number of record labels, as mentioned at the end of the previous post. Some would argue that if an album was released by Blue Note, Riverside, or Prestige, then that album is by definition hard bop. Conversely, if an album came out on Fantasy Records, then that record is by definition cool jazz, according to this argument. Though Blue Note, Riverside, and Prestige released many hard bop records, and Fantasy released many cool jazz records, all of these labels were much more diverse than this argument indicates. Blue Note, after all, released a lot of great avant-garde records in the 1960s (Eric Dolphy's Out To Lunch and Ornette Coleman's Live at The Golden Circle come to mind), just to give one example of an exception. Defining a subgenre of jazz by which label it appeared on probably creates more confusion than clarification.