Seizō Watase (わたせ せいぞう or 渡瀬 政造, Watase Seizō) is a Japanese manga artist and illustrator born 15 February 1945 in Kobe, Hyōgo Prefecture, Japan. Outside of being an illustrator for numerous posters, books, and other works, he is most well known for his dramatic romance manga , which had sold over 5 million copies. He won the 1974 Shogakukan Big Comic Prize. In 1987, Watase received the Bungeishunjū Manga Award for his work Phillip, P.I. (私立探偵フィリップ, Shiritsu Tantei Firippu).