principle of reciprocity
Used in legal, diplomatic, and economic contexts to describe a policy where one party's actions toward another are mirrored. Often appears in phrases like 相互主義に基づく (based on the principle of reciprocity).
The treaty was concluded based on the principle of reciprocity.
From the standpoint of reciprocity, we request similar measures from the other country.
互恵主義 emphasizes mutual benefit, while 相互主義 focuses on the principle of responding in kind, which may not always be beneficial.
相互 is the broader term meaning 'mutual' or 'reciprocal'; 相互主義 specifically refers to the doctrine or principle.
bilateralism
Compound of 相互 (mutual, reciprocal) and 主義 (principle, doctrine). The term is a direct translation of the Western concept of reciprocity in international relations and law.