"To his credit, William immediately corrected himself: "... um, Japanese food.
"In recent weeks you have seen nature at its cruellest and on behalf of my family I wanted you to know that our thoughts and prayers are with all those who have been affected", William said at the official opening of Japan House London where he was joined by Japan's Deputy Prime Minister Taro Aso. Have you had much Japanese food? No?
The duke also sipped sake rice wine in a morning toast, and tried some "delicious and amazing" salmon sashimi prepared specially by famed chef Akira Shimizu.
Chuckling, William replied: "Yes, I'm quite exhausted, has it been a long day for you too?"
"My wife and I love sushi", William said.
Japan House aims to deepen understanding of the East Asian island nation as it prepares to host both the 2019 Rugby World Cup and the 2020 Tokyo Olympic and Paralympic Games.
He finished by unveiling a plaque and leading a traditional kanpai toast, where sake is enjoyed from a wooden cup called a masu.
Western Japan was hit last week by the strongest typhoon to strike the country in 25 years, and then just days later by an natural disaster that paralyzed the northernmost main island of Hokkaido and left more than 40 dead.
The Duke of Cambridge was at the opening of a cultural centre celebrating Japan.
William added that he had been "deeply honoured" to visit Japan three years ago where he saw the "wonderful blend of ancient and modern which so characterises your fantastic country".