user: Question: What date was the participant/recipient  Takakazu Watanabe?
Columns: ['Film Festival', 'Date of ceremony', 'Category', 'Participants/Recipients', 'Result']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['34th Japan Academy Prize', '18 February 2011', 'Best Film', 'Otōto', 'Nominated']
SQL:

assistant: SELECT "Date of ceremony" FROM "Table" WHERE "Participants/Recipients" = 'Takakazu Watanabe';