The ruling triumvirate railroaded a contentious bill to revise the electoral system Friday by voting on it at an Upper House committee amid an opposition boycott.
The vote by members of the Liberal Democratic Party, New Komeito and New Conservative Party came in the ad hoc House of Councilors committee.
Opposition parties have been boycotting virtually every Diet session since last week to protest the coalition's submission of the bill to revise the Public Offices Election Law.