A four-character idiom describing a situation where one force (party, company, team, etc.) is very strong while many others are weak; used for politics, markets, sports, etc.
その業界は一強多弱で、新規参入が難しい。
That industry is dominated by one strong player and many weak ones, making it hard for newcomers to enter.
選挙では一強多弱の構図が長年続いている。
The electoral landscape has been a one-strong-many-weak structure for years.