“You must not eat here.” (Rule)
“Please don’t eat this.” (Request)
Both mean “Don’t eat,” but the vibe is completely different. 〜てはいけません (Te wa ikemasen) is for authority and rules. 〜ないでください (Nai de kudasai) is for asking nicely. Let’s master the difference with Joy and Ken!
🗣 Conversation Scene
Joy is hungry in the library, and then later at home.
（家に帰って）あ、このプリン美味しそう！食べちゃおうかな。
((In Library) I’m hungry… I’ll eat this burger. (At Home) Oh, this pudding looks good! Maybe I’ll eat it.)
図書館（としょかん）で 食べてはいけません！（ルール）
あと、それは僕のプリンだから 食べないでください。（お願い）
(Joy, no! You “must not eat” in the library! [Rule] Also, that’s my pudding, so “please don’t eat” it. [Request])
💡 Explanation
Are you enforcing a law? Or asking a favor?
Point 1: 〜ては いけません (Te wa ikemasen)
Meaning: You must not… / It is forbidden.
This is a strong prohibition. It implies rules, regulations, or laws. It sounds authoritative (like a teacher, police officer, or parent).
- ここで 写真（しゃしん）を 撮（と）っては いけません。
(You must not take photos here. [Museum Rule]) - お酒（さけ）を 飲んでは いけません。
(You must not drink alcohol. [Underage / Driving])
Point 2: 〜ないで ください (Nai de kudasai)
Meaning: Please do not… / Please refrain from…
This is a polite request. You are asking someone to stop doing something or not to do it for a personal reason.
- 行（い）かないで ください。
(Please don’t go. [I will be sad]) - 忘（わす）れないで ください。
(Please don’t forget.)
📊 Comparison Table
🚧 Joy’s Mistake
(Joy doesn’t want Ken to look at her diary)
❌ Wrong: 私の日記（にっき）を 見ては いけません！
(Tone: “It is against the law to read my diary!” You sound like a strict teacher. It’s too strong for a friend.)
✅ Right: 私の日記を 見ないで ください！
(Tone: “Please don’t read it, it’s private.” This is a proper request.)
🔥 Practice Quiz
Tap to check the answer!
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