Meaning & Usage
✨ Basic Meaning
To finish an action completely (completion), or to do something accidentally or regretfully (regret/trouble).
🎯 Primary Function
To add a nuance of finality (completion) or negative consequence (regret/accident) to a verb.
📋 Grammar Structure
Verb (Te-form) + しまう / ちゃう
N/A (Primarily for verbs, or I-adjectives must be changed to V-te form, e.g., 寒くなってしまう)
N/A (Primarily for verbs, or Na-adjectives must be changed to V-te form, e.g., 元気になってしまう)
V-te しまう + ない (e.g., してしまわない)
🎭 Usage Contexts
Formal Situations
Use the full form: 〜てしまいます / 〜てしまいました.
Informal Situations
Use the contracted form: 〜ちゃう / 〜じゃう.
Written Language
The full form (〜てしまう) is used, except in dialogue within narrative writing.
Spoken Language
The contracted forms (ちゃう/じゃう) are extremely common and necessary for sounding natural.
💡 Common Applications
Expressing Completion/Finality
Indicates that the action (reading) has been entirely finished, often with a sense of decisive completion.
Example: 全部読んでしまいました。(Zenbu yonde shimaimashita.)
Expressing Regret or Accident
Indicates that the action (dropping the wallet) was accidental or regrettable, often resulting in a negative consequence.
Example: 財布を落としちゃった。(Saifu o otochajatta.)
Colloquial Contraction (ちゃ/じゃ)
This is the casual, contracted form of 飲んでしまった (nonde shimatta), commonly used in spoken Japanese to express either completion or regret.
Example: 飲んじゃった。(Nonjatta.)
Frequency
Very High (essential for natural spoken Japanese)
Difficulty
Intermediate (JLPT N4/N3)
Tag:
Example Sentences
Example #1
宿題を全部やってしまいました。
Furigana: しゅくだいをぜんぶやってしまいました。
Romaji: Shukudai o zenbu yatte shimaimashita.
English: I finished all my homework.
Example #2
財布をバスの中に忘れてしまいました。
Furigana: さいふをバスのなかにわすれてしまいました。
Romaji: Saifu o basu no naka ni wasurete shimaimashita.
English: I accidentally left my wallet on the bus.
Example #3
ケーキを全部一人で食べちゃった。
Furigana: ケーキをぜんぶひとりでたべちゃった。
Romaji: Kēki o zenbu hitori de tabechatta.
English: I ended up eating the entire cake by myself.
Example #4
傘を忘れて行っちゃだめだよ。
Furigana: かさをわすれていっちゃだめだよ。
Romaji: Kasa o wasurete iccha dame da yo.
English: Don’t forget the umbrella and leave!
Example #5
このレポートは明日までに必ず終わらせてしまいます。
Furigana: このレポートはあしたまでにかならずおわらせてしまいます。
Romaji: Kono repōto wa ashita made ni kanarazu owarasete shimaimasu.
English: I will definitely finish this report by tomorrow.
Example #6
見た時に買っておけばよかったのに、売り切れちゃった。
Furigana: みたときに買っておけばよかったのに、うりきれちゃった。
Romaji: Mita toki ni katte okeba yokatta noni, urikirechatta.
English: I should have bought it when I saw it, but now it’s sold out!
Example #7
猫はどこへ行ってしまったんだろう？
Furigana: ねこはどこへいってしまったんだろう？
Romaji: Neko wa doko e itte shimatta n darō?
English: Where has the cat gone off to?
Example #8
新しい花瓶を壊しちゃった。
Furigana: あたらしいかびんをこわしちゃった。
Romaji: Atarashii kabin o kowashichatta.
English: I accidentally broke the new vase.
Example #9
ごめんなさい、会議のことをすっかり忘れてしまいました。
Furigana: ごめんなさい、かいぎのことをすっかりわすれてしまいました。
Romaji: Gomennasai, kaigi no koto o sukkari wasurete shimaimashita.
English: I’m sorry, I completely forgot about the meeting.
Example #10
そのままにしておくと、アイスクリームが溶けちゃうよ。
Furigana: そのままにしておくと、アイスクリームがとけちゃうよ。
Romaji: Sonomama ni shite oku to, aisukurīmu ga tokechau yo.
English: If you leave it like that, the ice cream will melt away.
Notes & Nuances
📌 Important Points
Irreversibility and Finality
The “regret” meaning often implies a strong feeling of finality or an irreversible outcome, much like saying “it’s done for.”
Example: もう二度と遅刻しないように気をつけます。(Mō nido to chikoku shinai yō ni ki o tsukemasu.)
Emphasis on Thorough Completion
When used for completion, it emphasizes the thoroughness and definitive nature of the finished task.
Example: こんなに早く終わらせるなんてすごいですね。(Konna ni hayaku owaraseru nante sugoi desu ne.)
Expression of Trouble or Accident
This structure is key to expressing mistakes or misfortunes where the speaker feels responsible or troubled by the outcome.
Example: 宿題を忘れてしまった。(Shukudai o wasurete shimatta.)
⚠️ Common Mistakes
❌ 忘れてしまっちゃった。
✅ Using the full form: 忘れてしまいました。
Students sometimes mix the casual verb form with the polite しまいます ending. The full pattern must be followed for formality.
❌ お金を使った。（ regret context)
✅ お金を使ってしまった。(Okane o tsukatte shimatta.)
In the ‘regret’ context, てしまう implies the action was done completely or accidentally. Simply using the plain past tense (使った) misses this nuance.
❌ 食べるしまう (taberu shimau)
✅ 「てしまう」 is used with the Te-form.
The base form must always be converted to the Te-form before adding しまう/ちゃう.
🏛️ Cultural Context
Politeness Level: The full form (てしまいます) is polite. The contracted form (ちゃう/じゃう) is casual.
Social Situations: Use the contracted form only with family, close friends, or subordinates. Use the full form with superiors or in formal business settings.
Regional Variations: The contraction ちゃう/じゃう is standard across most regions for casual speech, though variations in pitch and speed exist.
🔍 Subtle Differences
V-てしまう vs. V-た
V-た is simple past. V-てしまう adds the nuance of completion, finality, or regret/accident.
When to use: Use V-てしまう when you want to emphasize the thoroughness of the action or express an unfortunate outcome.
V-てしまう vs. V-ておく
V-てしまう means “to finish/regret.” V-ておく means “to do something in advance” (preparation) or “to leave something as it is.”
When to use: Contrast them: 食べちゃった (I ate it all up) vs. 食べておいた (I ate it in advance/I left it eaten).
📝 Conjugation Notes
The contraction follows the Te-form rules: * Verbs ending in 〜てしまう contract to 〜ちゃう. * Verbs ending in 〜でしまう contract to 〜じゃう (e.g., 読んでしまう -> 読んじゃう; 死んでしまう -> 死んじゃう).
🔊 Pronunciation Tips
When pronouncing ちゃう and じゃう, make sure the “ch” and “j” sounds are crisp. In fast speech, the preceding vowel often merges, making the contraction very smooth.
🧠 Memory Tips
Think of しまう as “closing the lid” on an action. When the lid is closed, the action is finished (completion), or the mistake is sealed and irreversible (regret).
Other Grammar
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