Japan is voting in a parliamentary election that has half of the seats in the upper house of parliament up for grabs. Prime Minister Shinzo Abe is hoping for backing for his economic policies.
If he can achieve a two-thirds majority in the upper house to match that in the lower house, he could hold a referendum on constitutional change.
Polling stations close at 20:00 local time (1100 GMT) with results expected shortly after, BBC reported.
Abe’s ruling Liberal Democratic Party currently has 116 seats in the 242-strong upper house and can also count on Komeito’s 20 seats.
The BBC’s Steve Evans in Tokyo says Abe has fought his campaign on his economic record, but the sub-text of the election has been the ability to change the constitution.
Abe is thought to want to change Article 9, the so-called pacifism clause that forbids Japan from fighting wars abroad.
Some in the country view as unfair the constraint on Japan imposed by the US as WW2 victors 70 years ago and the rise of China has reinforced the view on the right that the clause should go.
The opposition has asked voters to reject any adoption of a more assertive military role.
Abe has based his election campaign on his economic policies, although he admits himself that his Abenomics, aimed at ending debilitating deflation, are only “half done”.
This is the first nationwide election since the voting age was lowered from 20 to 18.
