TOKYO • Late in December, Mr Taro Kono, the Foreign Minister of Japan, was hospitalised to have a ureteral stone removed. That night, he appeared at a party for the 84th birthday of Emperor Akihito.
The next day, he campaigned on behalf of a mayoral candidate on the southern island of Kyushu, almost 965km from Tokyo. A day later, on Christmas Eve, he flew to Tel Aviv, Israel, to begin a five-day trip to the Middle East.
It was the kind of relentless schedule, well documented on social media, that brought to mind a candidate for higher office.
Which is what Mr Kono is - just one who does not know when his race may start.
Last autumn, Prime Minister Shinzo Abe won a big election victory that put him on track to become the country's longest-serving leader in modern times.
Mr Abe, 63, has indicated he has no imminent plans to retire: He wants to stay in office at least until the Tokyo Olympics in 2020, and the governing Liberal Democratic Party (LDP) changed its rules last year to allow him to do so.
But a new generation of politicians is already positioning itself to succeed him. Mr Kono, 55, is one of the most intriguing, bringing a maverick streak to Japan's usually stodgy political world.
But he will face big challenges. An American-educated, political blue blood and a liberal-leaning non-conformist within the conservative governing party, he is trying to position himself as a contender for the country's top office while still departing from the party's right wing on issues like nuclear power and immigration.
In an interview at the Foreign Ministry last month, Mr Kono smiled impishly when asked how soon he might make a bid to lead the LDP. "You never know," he said. "Who predicted President Trump two years ago?"
Until being appointed to the Cabinet in August, Mr Kono, who speaks English fluently and left Tokyo's prestigious Keio University to study at Georgetown University in Washington, was not usually on the list of potential heirs to Mr Abe, given his, sometimes, more liberal views.
He is also the son of Mr Yohei Kono, a previous foreign minister who, as chief Cabinet secretary in 1993, issued a breakthrough apology to women from Korea and elsewhere who were forced to work as sex slaves in Japanese military brothels during World War II.
Nationalists in the governing party have long resented the Kono statement, with some holding it against the son.
With an eye on persuading his own party to consider him for the top office, Mr Kono has toned down some of his views and aligned himself with the administration.
Still, the rebel peeks out.
In a speech last month in Abu Dhabi, United Arab Emirates, Mr Kono criticised Japan's "lamentable" energy policy and exhorted his country to expand renewable energy.
But Mr Kono stays on the party's message on key issues, including keeping up pressure on North Korea and adhering to a 2015 agreement with South Korea to resolve the dispute over the comfort women who worked in military brothels.
"He's been mostly very much toeing the Abe line," said Dr Kristi Govella, assistant professor of Asian studies at the University of Hawaii at Manoa.
"But there are some cases where he has been willing to say, this is not the best policy."