A kohai is a junior member in a hierarchy defined by experience or joining date.
Word in 30 Seconds
- Refers to someone younger or with less experience.
- Commonly used in school and business settings.
- The opposite of a senior colleague (senpai).
使用パターン
基本的に「先輩（せんぱい）」の対義語として使われます。自分より先に入った人、あるいは年上の経験者を「先輩」と呼び、それ以外の後から来たメンバーを「後輩」と呼びます。親しい間柄では呼び捨てにすることもありますが、基本的には名前の後ろに「さん」や「くん」を付けて呼ぶのが一般的です。
一般的な文脈
学校（部活動や学年）、職場（入社年度）、習い事（道場など）で頻繁に使用されます。特に日本の体育会系文化やビジネスシーンでは、先輩・後輩の関係性が非常に重視され、礼儀やマナーが求められる場面が多いです。
類似語との比較
「年下（としした）」は純粋に年齢が若いことを指しますが、「後輩」は年齢に関係なく、組織内での序列や経験の差を指す点が異なります。例えば、自分より年上でも、会社に入ったのが後であれば、その人は「後輩」になります。
Examples
昨日、新しい後輩が入ってきました。
everydayA new junior colleague joined yesterday.
後輩の指導を担当することになりました。
formalI have been assigned to mentor my junior colleague.
部活の後輩とご飯を食べに行く。
informalI'm going out to eat with my junior from the club.
研究室の後輩が論文を書いている。
academicMy junior in the lab is writing a thesis.
Common Collocations
Common Phrases
後輩を可愛がる
to treat a junior with affection
生意気な後輩
a cheeky junior
後輩の面倒を見る
to take care of a junior
Often Confused With
Toshishita refers strictly to age. Kohai refers to the hierarchical position in a group.
Doryo means colleague or peer at the same level. Kohai implies a vertical relationship.
Grammar Patterns
How to Use It
Usage Notes
The term is used to describe a subordinate position in a hierarchy. While it is not inherently rude, calling someone 'kohai' directly to their face is often considered impolite. Always use the person's name or title to maintain proper social etiquette.
Common Mistakes
Learners often use 'kohai' to mean anyone younger than them, regardless of the setting. Remember that it only applies to shared organizations or groups. Also, avoid using it as a direct address like 'Hey, kohai!' as it sounds condescending.
Tips
Use with names for politeness
Always add a suffix like 'san' or 'kun' when addressing a junior. It maintains a respectful atmosphere even if you are the senior.
Avoid direct labeling
Do not call someone 'kohai' to their face as a title. It can sound patronizing or overly formal.
Hierarchy is key in Japan
Understanding the senpai-kohai dynamic is essential for navigating Japanese social life. It dictates communication styles and responsibilities.
Word Origin
The word is composed of 'Ko' (after/behind) and 'Hai' (to enter/attend). It literally refers to one who entered a group after another.
Cultural Context
The senpai-kohai relationship is the bedrock of Japanese social structure. It promotes mentorship and passing down knowledge, but also requires juniors to show deference to those with more experience.
Memory Tip
Think of 'Ko' as 'small/young' and 'Hai' as 'following'. A junior is someone who follows behind you in experience.
Frequently Asked Questions
4 questionsはい、あります。会社や部活動などで、自分より後に入ってきた人であれば、年齢が上であっても「後輩」と呼びます。
親しい間柄ならタメ口で話すことも多いですが、ビジネスの場や初対面の相手には、丁寧語を使うのが無難です。
相手の名前＋さん、あるいは名前＋くんと呼ぶのが一般的です。親しい場合はニックネームで呼ぶこともあります。
「あなたは後輩です」と言うことはほとんどありません。あくまで第三者に説明する際や、関係性を示す際に使います。
Test Yourself
彼は私より一年後に入社したので、私の___です。
後から入社した人は後輩です。
「後輩」という言葉の使い方は？
組織内での経験や加入時期が基準となります。
（後輩 / 教えた / を / 私は / 仕事）
助詞の使い方が正しい文です。
Score: /3
Summary
A kohai is a junior member in a hierarchy defined by experience or joining date.
- Refers to someone younger or with less experience.
- Commonly used in school and business settings.
- The opposite of a senior colleague (senpai).
Use with names for politeness
Always add a suffix like 'san' or 'kun' when addressing a junior. It maintains a respectful atmosphere even if you are the senior.
Avoid direct labeling
Do not call someone 'kohai' to their face as a title. It can sound patronizing or overly formal.
Hierarchy is key in Japan
Understanding the senpai-kohai dynamic is essential for navigating Japanese social life. It dictates communication styles and responsibilities.
Examples
4 of 4昨日、新しい後輩が入ってきました。
A new junior colleague joined yesterday.
後輩の指導を担当することになりました。
I have been assigned to mentor my junior colleague.
部活の後輩とご飯を食べに行く。
I'm going out to eat with my junior from the club.
研究室の後輩が論文を書いている。
My junior in the lab is writing a thesis.
Related Content
This Word in Other Languages
Related Grammar Rules
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