Quadruple VS
Synonym Boundary: "理由", "所以", "国家理性", "理"
All represent the core concept "reason", but require precise selection.
Japanese Option A
理由
りゆう (riyū)
N4 / CEFR
Japanese Option B
所以
ゆえん (yuen)
N1 / CEFR
Japanese Option C
国家理性
こっかりせい (kokkarisei)
C2 / CEFR
Japanese Option D
理
ことわり
C2PLUS / CEFR
Quadruple VS Nuance Contrast & Social Differences
When expressing "reason" in Japanese, you must carefully distinguish between "理由", "所以", "国家理性", "理" based on context.
- 理由 (りゆう (riyū) - Level: N4): Maps to "reason, motive" and is used when A noun referring to the cause or explanation for something. Often used with なぜ.
- 所以 (ゆえん (yuen) - Level: N1): Maps to "reason; cause; origin; source; the reason why..." and is used when A formal and somewhat literary term. Often used in the pattern 「〜の所以」 or 「〜する所以」 to explain the fundamental reason, origin, or essence of something, implying 'the very reason why something is as it is'..
- 国家理性 (こっかりせい (kokkarisei) - Level: C2): Maps to "reason of state / raison d'état" and is used when Essential structural term in CEFR C2 vocabulary syllabus..
- 理 (ことわり - Level: C2PLUS): Maps to "reason; principle; logic; truth (classical usage)" and is used when Essential structural term in CEFR C2PLUS vocabulary syllabus..
Context for "理由"
遅刻した理由を教えてください。
Please tell me the reason for being late.
Context for "所以"
彼が成功した所以は、たゆまぬ努力にあった。
The reason he succeeded was his tireless effort.
Context for "国家理性"
私は国家理性に興味があります。
I am interested in reason of state / raison d'état.
Context for "理"
私は理に興味があります。
I am interested in reason; principle; logic; truth (classical usage).
Synonym Mastery Challenge
Which Japanese word perfectly fits this blank space?
Fill in the blank: "遅刻した ＿＿＿ を教えてください。" (Meaning: "Please tell me the reason for being late.")
🎉 Correct Answer!
Remember: "理由" is correct here because it represents "reason, motive" in the context: "Please tell me the reason for being late.".