Historically, regional banks in the same areas tend to merge over time, reducing overheads while increasing their strength and regional footprint.
[2] The regional bank is in contrast to a city bank (toshi ginkō 都市銀行 or togin 都銀) or "megabank" with its head office in metropolitan Tokyo, Nagoya, or Osaka.
Each of these banks have a large footprint and a wide network of branches in the larger cities of Japan.
They are also different to a shinkin bank (shin-yō kinko 信用金庫) which are cooperative regional financial institutions serving small and medium enterprises and local residents.
[5] This is a partial list of the 100 current regional banks by broad geographic area (from north to south):