What is "aizu"

n. A region in western Fukushima prefecture. Primary city is 会津若松 (あいづわかまつ, ''Aizu Wakamatsu'').

is the westernmost of the three regions of Fukushima Prefecture in Japan, the other two regions being Nakadōri in the central area of the prefecture and Hamadōri in the east. As of October 1, 2010, it had a population of 291,838. The principal city of the area is Aizuwakamatsu.

During the Edo period, Aizu was a feudal domain known as . It was part of Mutsu Province; the area once was part of Iwase Province in the 8th century and, before the prefectural system, Iwashiro Province. Although never an official province in its own right, Aizu was considered as such de facto, and even today local Japan Rail stations prefix "Aizu-" to names instead of "Iwashiro-", as it was for stations around the center of Fukushima Prefecture.