Naoki Tada, along with brother Takashi, inherited stake in discount drugstore chain Sundrug.

FORBES: Magazine Article

Also making debuts are the Tada brothers, who share a stake in discount drug chain Sundrug, and Hirokazu Sugiura, founder of Sugi Pharmacy.

FORBES: Magazine Article

Another potential drop-off is Japan's Katsumi Tada.

FORBES: Bye, Bye Billions