"Real Jazz" only consists of the New Orleans Swing scene and the late 50's Bebop scene. What is known by "Jazz Fusion" is nothing but Funk with questionable real Jazz influence. When people try to argue that bands like Kenny G are not real Jazz, while saying that Casiopea is, I can't help not to cringe because they are just as fake Jazz as Kenny G (plus the pretentiousness).
Real Jazz sounds ENERGETIC, POWERFUL and somewhat EXPAREMENTAL. Fake Jazz is weak, soft, and a failed attempt to direct energy and emotion into music.
Some examples of REAL Jazz are Chick Corea, John Coltrane, Chet Baker (the only real Jazz Cat from the west coast scene) and Ornette Colman.
Some examples of FAKE Jazz are Casiopea, Herbie Hancock and Frank Zappa
JAZZ BELONGS TO BEBOP
NOT TO FUNK, POP , PROG ROCK OR ANY OTHER MAINSTREAM GENRE

/j
(Its a copypasta)