Donald Keene graduated from university in 1942 and studied Japanese under the auspices of the U.S. Navy before working in military intelligence during World War Two, interrogating prisoners and translating documents.

Donald Keene, a scholar of Japanese literature who became the first foreigner to receive the country's highest cultural award, died of heart failure at a Tokyo hospital on Sunday.

Keene, 96, was known for introducing Japan's culture in the United States and around the world through his scholarship and translations of classical and modern Japanese literature.

“It was all of sudden. I was shocked,” Akira Someya, the director and secretary-general of the Donald Keene Centre in the northern city of Kashiwazaki, told Reuters.

Keene, who befriended giants of Japanese literature such as Yukio Mishima and Yasunari Kawabata, was awarded the Order of Culture in March 2008, the first non-Japanese to receive it, and became a Japanese citizen in 2012.

He graduated from university in 1942 and studied Japanese under the auspices of the U.S. Navy before working in military intelligence during World War Two, interrogating prisoners and translating documents.

Keene went on to a career as a scholar of Japanese literature and was credited with a key role in winning recognition for “The Tale of Genji”, an 11th-century masterpiece often called the world's first novel, as world-class literature.

After more than half a century teaching at Columbia University, Keene moved to Tokyo full-time and took Japanese citizenship following the devastating earthquake and nuclear disaster in northeast Japan in 2011.