Kansai is not a
prefecture, it is a
region encompassing a number of prefectures. The literal meaning of the word is "west of the barrier", with
barrier meaning the (imaginary) wall dividing the west (Kansai) from the east (
Kanto) of Japan; actually it's more a division between the
Kyoto-
Osaka region where the focus of power and history in Japan
used to be, and the
Edo/
Tokyo
region that was always economically powerful but used to be considered wild and uncivilized until the
Tokugawa shogunate reversed the power balance.
Nowadays, Tokyo is the center of Japan, and Kansai people are seen as somewhat odd, and funny, partially because of their distinctive accent, Kansai-ben.