Naoto Kan, president of the Democratic Party of Japan, on Tuesday defended the decision by his eldest son to run for a seat in the House of Representatives.

Gentaro Kan, 30, plans to seek election from the Okayama No. 1 constituency.

If successful, Gentaro Kan could join the large number of "nisei" (second-generation) lawmakers in the Diet, who are often accused of dominating the nation's political arena by inheriting the election machines of their forbears.

Nisei lawmakers have also been cited as a symbol of the closed nature of Japanese politics and of the barriers facing ordinary citizens who wish to participate.

Indeed, about one-third of the roughly 350 Diet members representing the Liberal Democratic Party are either the offspring or grandchildren of former Diet members.

During a news conference in Tokyo, the DPJ chief, who was elected to the Lower House from Tokyo's No. 18 electoral district, stressed that his son would start from scratch in Okayama. The grave of Naoto Kan's father is located in Okayama's No. 1 constituency, as is a small forestry owned by the DPJ chief.

"I haven't done any political activities in Okayama. There would be no problems in that sense," Kan said, arguing that the problem with nisei lawmakers is that they easily inherit the election machines of their forbears.

Naoto Kan's wife, Nobuko, is also from Okayama, although her hometown is outside the No. 1 constituency.

Naoto Kan also emphasized that the DPJ itself had asked the younger Kan to run in the Lower House election, which must be held by June next year.

"It's a voluntary decision (by Gentaro Kan)," the DPJ chief said.