English: Telephone numbers in Kanto Region in Japan, by the three upper digits(partly two upper digits: 03 and 06 area). As of May 2016 and source is the Ministry of Internal Affairs and Communications of Japan. See also Telephone numbers in Japan on Wikipedia.
Note: Disits of area code of Japan are 1 to 4, because they're different by areas. This figure simply shows three upper digits, not shows full area codes.