Japanese firms outspent their Chinese rivals for the second year in a row to be the biggest deal-making force in Asia in 2019, aided by favorable financing and reduced competition in the face of U.S.-China tensions.

Over $200 billion of domestic and foreign deals shook up Japan's business landscape last year, and the buying is set to continue into 2020 as a dwindling population spurs greater outbound buying.

A corporate governance overhaul is also forcing companies to rethink long-held beliefs around mergers and acquisitions.