Official campaigning commenced on Thursday for a House of Councilors by-election in western Japan — the first national contest since Prime Minister Fumio Kishida revamped his Cabinet last month in a bid to re-energize his political base.

The Upper House race in the Tokushima-Kochi district kicked off before campaigning for a House of Representatives by-election starts next Tuesday. The two by-elections on Oct. 22 are expected to be one-on-one battles between the ruling and opposition forces.

The by-elections come as the approval ratings for Kishida's Cabinet have slumped to the lowest levels since he became prime minister in October 2021, due in part to public frustration over surging prices and insufficient wage growth.