Phrase in 30 Seconds
A fundamental Japanese phrase used to highlight priorities, essential advice, or the core meaning of a situation.
- Means: 'An important thing' or 'something significant' in any context.
- Used in: Giving advice, summarizing meetings, or expressing personal values.
- Don't confuse: With '{大事|だいじ}にする', which means 'to cherish' or 'take care'.
Explication à ton niveau :
Signification
Something of significance or high value.
Contexte culturel
The phrase 'O-daiji ni' is used when someone is sick. It's a shortened version of 'Treat your body as an important matter.' In Japanese meetings, the 'important thing' is often saved for the end or introduced with 'Kekkyoku...' (In the end...). Japanese teachers use 'Daiji na koto' to signal that a specific point will be on the entrance exams (Juken). Influencers use '#{大事|だいじ}なこと' to share daily wisdom or life hacks with their followers.
The 'Na' Rule
Always remember that '{大事|だいじ}' is a na-adjective. If you forget the 'na', it sounds like 'Important thing' without the grammar connecting them.
Koto vs Mono
Don't use '{大事|だいじ}なこと' for your physical treasure. Use '{大事|だいじ}なもの' for your cat, your car, or your phone.
The 'Na' Rule
Always remember that '{大事|だいじ}' is a na-adjective. If you forget the 'na', it sounds like 'Important thing' without the grammar connecting them.
Koto vs Mono
Don't use '{大事|だいじ}なこと' for your physical treasure. Use '{大事|だいじ}なもの' for your cat, your car, or your phone.
Sentence Starter
Start a sentence with '{大事|だいじ}なことは、...' to sound more authoritative and clear in your speech.
O-daiji ni
When you hear someone sneeze or say they are sick, just say 'O-daiji ni!' It's the most natural response.
Teste-toi
Fill in the missing particle.
{大事|だいじ} ( ) ことです。
'{大事|だいじ}' is a na-adjective, so it needs 'na' to connect to a noun.
Which sentence is most natural for 'Health is important'?
Choose the best option:
Health is an abstract concept, so '{こと|koto}' is the correct noun.
Complete the dialogue.
A: {仕事|しごと}で{何|なに}が{一番|いちばん}{大事|だいじ}ですか？ B: ( ) が{一番|いちばん}{大事|だいじ}なことだと{思|おも}います。
'{笑顔|えがお}' (smile) is a noun that fits the context of what is important at work.
Match the phrase to the situation.
When would you say '{大事|だいじ}なことを{忘|わす}れました'?
'Koto' refers to abstract things like information or tasks.
🎉 Score : /4
Aides visuelles
Koto vs Mono
Banque d exercices
5 exercices{大事|だいじ} ( ) ことです。
'{大事|だいじ}' is a na-adjective, so it needs 'na' to connect to a noun.
Choose the best option:
Health is an abstract concept, so '{こと|koto}' is the correct noun.
A: {仕事|しごと}で{何|なに}が{一番|いちばん}{大事|だいじ}ですか？ B: ( ) が{一番|いちばん}{大事|だいじ}なことだと{思|おも}います。
'{笑顔|えがお}' (smile) is a noun that fits the context of what is important at work.
When would you say '{大事|だいじ}なことを{忘|わす}れました'?
'Koto' refers to abstract things like information or tasks.
🎉 Score : /5
Questions fréquentes
10 questions{大事|だいじ} is more objective (serious, important for a goal), while {大切|たいせつ} is more subjective (precious, emotionally valuable).
Yes, it means an 'important person,' usually in a functional or social sense (like a key client). For a loved one, '{大切|たいせつ}なひと' is more common.
Yes, but for very formal documents, '{重要|じゅうよう}な{事項|じこう}' (important items) is preferred.
Use '{一番|いちばん}{大事|だいじ}なこと' (Ichiban daiji na koto).
It's better to use '{秘密|ひみつ}' (himitsu) or '{大事|だいじ}な{話|はなし}' (an important talk).
It can be both, but in this phrase, it functions as a na-adjective.
It means 'Take care of yourself' or 'Get well soon.'
Yes, it means 'It's not an important thing' or 'It doesn't matter.'
'Koto' creates a noun phrase that refers to a specific matter or fact, which is more substantial than just using 'no'.
Yes, characters often use it before a big reveal or when discussing their 'way of the ninja' or values.
Expressions liées
{大切|たいせつ}なこと
similarA precious/cherished thing
{重要|じゅうよう}なこと
specialized formAn important matter
{大事|だいじ}にする
builds onTo cherish or take care of
{肝心|かんじん}なこと
similarThe crucial point
{必要|ひつよう}なこと
similarA necessary thing
Où l'utiliser
Job Interview
Interviewer: {仕事|しごと}で{一番|いちばん}{大事|だいじ}なことは{何|なに}だと{思|おも}いますか？
Candidate: チームワークが{一番|いちばん}{大事|だいじ}なことだと{思|おも}います。
Doctor's Visit
Doctor: {毎日|まいにち}{薬|くすり}を{飲|の}むのは{大事|だいじ}なことですよ。
Patient: はい、わかりました。{気|き}をつけます。
Parental Advice
Mother: {大事|だいじ}なことを{言|い}うから、よく{聞|き}いて。
Child: なあに？お{母|かあ}さん。
School Orientation
Teacher: これから{学校|がっこう}の{規則|きそく}について、{大事|だいじ}なことを{話|はな}します。
Student: （メモを{取|と}る）
Tech Support
Support: パスワードを{教|おし}えないのは、セキュリティで{一番|いちばん}{大事|だいじ}なことです。
User: そうですね。{注意|ちゅうい}します。
Travel Planning
Friend A: パスポートを{持|も}った？それが{一番|いちばん}{大事|だいじ}なことだよ！
Friend B: あ、{忘|わす}れてた！ありがとう！
Mémorise-le
Moyen mnémotechnique
Think of 'Die-Ji' as 'Die-Just' — if you were about to die, what would just be the most important thing?
Association visuelle
Imagine a giant (Dai) golden key (Koto) that unlocks a treasure chest. The key is the 'important thing' you need.
Rhyme
Daiji na koto, don't let it go-to!
Story
A monk is carrying a massive (Dai) scroll about a serious matter (Ji). He tells a student, 'This is the most important thing (Koto) you will ever read.'
In Other Languages
Similar to 'The main thing' in English or 'Lo esencial' in Spanish. Most languages have a way to nominalize the concept of importance.
Word Web
Défi
Write down three things that are '{大事|だいじ}なこと' to you today using the pattern: '[Noun] は {大事|だいじ}なことです。'
Review this phrase whenever you are setting goals or making a to-do list.
Prononciation
The 'dai' is like 'die' in English, and 'ji' is like the 'jee' in 'jeep'.
Short, flat 'na'.
Both 'o' sounds are short, like in 'boat' but without the 'u' sound at the end.
Spectre de formalité
{健康|けんこう}が{最|もっと}も{肝要|かんよう}な{事項|じこう}でございます。 (Discussing lifestyle)
{健康|けんこう}が{一番|いちばん}{大事|だいじ}なことです。 (Discussing lifestyle)
{健康|けんこう}が{一番|いちばん}{大事|だいじ}だよ。 (Discussing lifestyle)
{健康|けんこう}マジ{大事|だいじ}。 (Discussing lifestyle)
Derived from the Buddhist term 'Daiji' (Great Matter), referring to the fundamental questions of existence.
Le savais-tu ?
The kanji for 'Ji' (事) originally depicted a hand holding a tool to record events, emphasizing its meaning as a 'matter' or 'deed'.
Notes culturelles
The phrase 'O-daiji ni' is used when someone is sick. It's a shortened version of 'Treat your body as an important matter.'
“A: {風邪|かぜ}をひきました。 B: お{大事|だいじ}に。”
In Japanese meetings, the 'important thing' is often saved for the end or introduced with 'Kekkyoku...' (In the end...).
“{結局|けっきょく}、これが{一番|いちばん}{大事|だいじ}なことです。”
Japanese teachers use 'Daiji na koto' to signal that a specific point will be on the entrance exams (Juken).
“ここ、テストに{出|で}る{大事|だいじ}なことですよ！”
Influencers use '#{大事|だいじ}なこと' to share daily wisdom or life hacks with their followers.
“【#{大事|だいじ}なこと】{朝|あさ}の{習慣|しゅうかん}が{人生|じんせい}を{変|か}える。”
Amorces de conversation
{あなた|anata}にとって、{人生|じんせい}で{一番|いちばん}{大事|だいじ}なことは{何|なに}ですか？
{日本語|にほんご}を{勉強|べんきょう}するのに、{大事|だいじ}なことは{何|なに}だと{思|おも}いますか？
{仕事|しごと}を{選|えら}ぶとき、{一番|いちばん}{大事|だいじ}なことは{給料|きゅうりょう}ですか？
Erreurs courantes
{大事|だいじ}こと
{大事|だいじ}なこと
L1 Interference
これは{大事|だいじ}なものです (when referring to a concept)
これは{大事|だいじ}なことです
L1 Interference
{大事|だいじ}なことを{守|まも}る (to mean 'cherish')
{大事|だいじ}にする
L1 Interference
{大事|だいじ}なことのテスト
{大事|だいじ}なテスト
L1 Interference
In Other Languages
Important thing
Japanese uses the abstract noun 'koto' more frequently than English uses 'thing'.
Lo importante
Spanish doesn't require a word for 'thing' (koto) in this structure.
L'essentiel
French often prefers a single noun like 'l'essentiel' over an adjective+noun combo.
Das Wichtige
German uses capitalization to indicate the noun form.
الأمر المهم
Arabic requires the definite article on both the noun and the adjective.
重要的事情
Chinese uses 'shìqíng' which is slightly more concrete than the Japanese 'koto'.
중요한 것
Korean uses the word 'jung-yo' (重要) more often in daily speech than 'daiji'.
O importante
Like Spanish, it avoids a literal word for 'thing'.
Spotted in the Real World
“{大事|だいじ}な{人|ひと}、{忘|わす}れたくない{人|ひと}、{忘|わす}れちゃいけない{人|ひと}！”
The characters are trying to remember each other's names, which is the 'important thing' they must not forget.
“{最後|さいご}に{言|い}った{大事|だいじ}なこと...”
Lyrics referring to the last important thing said during a breakup.
“{人生|じんせい}で{一番|いちばん}{大事|だいじ}なことは、やりたいことをやることだと{思|おも}う。”
Commonly used in deep late-night conversations about life goals.
“{仲間|なかま}を{助|たす}けるのが、{一番|いちばん}{大事|だいじ}なことだ！”
Luffy emphasizing that saving his friends is his top priority.
“{大事|だいじ}なことなので2{回|かい}{言|い}いました。”
A common phrase used when someone repeats a point for emphasis.
Facile à confondre
Learners use 'koto' for physical objects.
Use 'mono' for things you can touch (keys, gifts) and 'koto' for things you can't (ideas, rules).
The kanji 'Daiji' is the same.
'Dai-jiken' means a major incident or crime, not just an important thing.
Questions fréquentes (10)
{大事|だいじ} is more objective (serious, important for a goal), while {大切|たいせつ} is more subjective (precious, emotionally valuable).
comparisonsYes, it means an 'important person,' usually in a functional or social sense (like a key client). For a loved one, '{大切|たいせつ}なひと' is more common.
usage contextsYes, but for very formal documents, '{重要|じゅうよう}な{事項|じこう}' (important items) is preferred.
grammar mechanicsUse '{一番|いちばん}{大事|だいじ}なこと' (Ichiban daiji na koto).
practical tipsIt's better to use '{秘密|ひみつ}' (himitsu) or '{大事|だいじ}な{話|はなし}' (an important talk).
usage contextsIt can be both, but in this phrase, it functions as a na-adjective.
grammar mechanicsIt means 'Take care of yourself' or 'Get well soon.'
cultural usageYes, it means 'It's not an important thing' or 'It doesn't matter.'
basic understanding'Koto' creates a noun phrase that refers to a specific matter or fact, which is more substantial than just using 'no'.
grammar mechanicsYes, characters often use it before a big reveal or when discussing their 'way of the ninja' or values.
cultural usage
