noun
checkbook diplomacy; chequebook diplomacy
A political term referring to the use of financial aid or economic incentives as a diplomatic tool, often with a critical nuance implying buying influence or goodwill.
その国は小切手外交で周辺国の支持を得ようとした。
That country tried to gain the support of neighboring countries through checkbook diplomacy.
Dollar diplomacy is a similar concept but specifically refers to the use of US dollar loans and investments to exert influence, historically associated with early 20th-century US foreign policy.
Compound of 小切手 (check, cheque) and 外交 (diplomacy), likely a calque from English 'checkbook diplomacy'.