By 1918 Sais was a highly popular and publicly recognizable film personality and was chosen by Japanese silent film matinee idol Sessue Hayakawa to appear opposite him in a series of film collaborations, the first being the 1918 racial drama "The City of Dim Faces" followed by "His Birthright", released the same year and also starring Hayakawa's actress wife Tsuru Aoki. Sais' collaboration with Hayakawa ended with the 1919 film "Bonds of Honor" and the same year Sais appeared with Swedish actress Anna Q. Nilsson in the moderately successful drama "The Vanity Pool".