Called Hainan jee fan(海南鶏飯), Singapore chicken rice has become popular in recent years in Japan. If you wish to have the most authentic one in Tokyo, I recommend the following places: Hainan Jee Fan Shokudo(海南鶏飯食堂) in Roppongi or Song Kee Jee Fan(松記鶏飯) in Awaji-cho, nearby Kanda.