Cognomen Seisaku (Seisaku 
) , worldwide, is a rare surname. The family name Seisaku is habitual in Eastern Asia, particularly Japan, where it is a rare surname, and China, where it is an extremely rare surname. Predominantly, Seisaku is the forename as well as the last name.
Abe, Yamada, Shimada, Shimizu, Kikuchi, Hayashi, Yoshida, Maruyama, Miyamoto, Sakamoto, Tsuchiya, Nakamura, Hasegawa, Furukawa, Ishikawa, Igarashi, Watanabe, Yamamoto, Yamazaki, Matsumoto, Kobayashi, Takahashi, Otsuka, Nomura, Tanaka, Kimura, Ito, Ono, Mori, Sato, Arai, Aoki, Kato, Kudo, Goto, Maeda, Hashimoto, Miura, Honma, Fujii, Inoue, Ishii, Ikeda, Okada, Ogawa, Masuda, Sasaki, Suzuki, Saito, and Yamaguchi