 Motoki , by then in his early 40s and having built a reputation as a realist , was cast as Daigo . Veteran actor Tsutomu Yamazaki was selected for the role of Sasaki ; Takita had worked with Yamazaki on We Are Not Alone ( 1993 ) . Although the character of Mika was initially planned as being the same age as Daigo , the role went to pop singer Ryōko Hirosue , who had previously acted in Takita 's Himitsu ( Secret ) in 1999 . Takita explained that a younger actress would better represent the lead couple 's growth out of naivety . In a 2009 interview , Takita stated that he had cast " everyone who was on my wish list " . 
