Shopping and sightseeing trips by Shotaro Kishida, Prime Minister Fumio Kishida's eldest son, while on a recent diplomatic tour has put the spotlight on the role of policy affairs secretaries in Japan’s political world.

The younger Kishida, who serves as the prime minister's executive secretary in charge of political affairs, was reported to have used official vehicles for shopping during his father’s visit to Paris, London and Ottawa in January.

His nomination as policy affairs secretary to the Cabinet last October drew allegations of nepotism and speculation that Fumio Kishida was clearing the way for his son to succeed him in parliament, with observers being surprised by the appointment given Shotaro's lack of political experience.