With Sunday's double victory in Tokyo and Fukuoka by-elections, Prime Minister Shinzo Abe might be feeling relieved — but not exactly over the moon.

At the very least, the commanding victories by two Liberal Democratic Party-affiliated candidates in the Lower House races provided him with a perfect excuse to claim that his Abenomics economic policy mix, as well as his ongoing push for Diet approval of the Trans-Pacific Partnership trade deal, received a strong public endorsement.

"We will continue to do our utmost to revitalize the economy to live up to the mandate given us by the voters in the by-elections," Chief Cabinet Secretary Yoshihide Suga said Monday.