There are 2 places named Kosai in Japan.
All places in the world called "Kosai".
Ono (18)
Ota (17)
Hongo (16)
Minato (15)
Wada (15)
Kawasaki (14)
Hama (14)
Ohama (14)
Tomari (14)
Nakamura (13)
Oshima (13)
Hara (13)
Nagahama (13)
Yoshida (12)
Okubo (12)
Sakai (12)
Hirose (11)
Kawaguchi (11)
Funakoshi (11)
Shinden (11)
Seto (11)
Okawa (11)
Kanayama (11)
Ogawa (10)
Ohara (10)
Nakayama (10)
Takata (10)
Oura (10)
Otani (10)
Shirahama (10)