Renho, one of the three candidates vying for the top slot in the Sept. 15 Democratic Party leadership election, has repeatedly denied speculation that she may be violating the Nationality Law by having de facto dual citizenship.

The high-profile lawmaker from the main opposition DP has a Taiwanese father and Japanese mother. On Wednesday, she denied the nationality allegations, telling Jiji Press and other media outlets that she had renounced her Taiwanese citizenship when she obtained Japanese nationality in 1985 at the age of 17.

But what are the legalities surrounding dual citizenship in Japan?