CREATE TABLE table_1315616_1 (date VARCHAR(255), mediator VARCHAR(255), red_team_host VARCHAR(255))
On what date was Keiichi Ubukata the mediator and Mitsuko Mori the red team host?
    
SQL: SELECT date FROM table_1315616_1 WHERE mediator = "Keiichi Ubukata" AND red_team_host = "Mitsuko Mori"