Meaning & Usage
โจ Basic Meaning
“Because it is not allowed to…” or “Since one must not…”
๐ฏ Primary Function
To provide a reason or justification (ใใ) for a subsequent action or statement, based on a rule or strong negative obligation/prohibition (ใฆใฏใใใชใ).
๐ Grammar Structure
V-ใฆ form + ใฏ + ใใใชใ + ใใ
Not typically used in this structure; applies to the inner part, e.g., i-adjective (stem) + ใใฆใฏ ใใใชใใใ.
Not typically used in this structure; applies to the inner part, e.g., na-adjective + ใงใฏ ใใใชใใใ.
Vใชใ (negative plain form) + ใงใฏ ใใใชใใใ (Double negative resulting in obligation: “Because you must V”). Less common than the direct prohibition form.
๐ญ Usage Contexts
Formal Situations
Used in formal settings (e.g., in company rules, official warnings) to explain rules, though the ‘ใฆใฏใใใชใ’ part itself is direct. In highly formal settings, ‘Vใฆใฏใชใใพใใใใ’ is sometimes preferred.
Informal Situations
Commonly used in informal speech among family and friends, especially when setting boundaries or reminding someone of a basic rule.
Written Language
Appears in written rules, instructions, and explanatory texts where the rule needs context.
Spoken Language
Very common in spoken language when clarifying or justifying a prohibition. The ‘ใใ’ at the end gives the sentence a natural conversational flow.
๐ก Common Applications
Stating the reason for a rule or prohibition.
Used when the speaker wants to explain the necessity of following a rule or the consequence of an action by citing the prohibition.
Example: ใใใซใดใใๆจใฆใฆใฏใใใชใใใใๅฟ
ใๆใกๅธฐใใพใใใใ (Since you must not throw away trash here, be sure to take it home.)
Giving a strong warning or instruction based on a rule.
Functions to justify a request or a command by providing the obligatory nature of the prohibition as the reason.
Example: ๆชๆๅนด่
ใซใ้
ใๅฃฒใฃใฆใฏ ใใใชใใใใ่บซๅ่จผๆๆธใ่ฆใใฆใใ ใใใ (We must not sell alcohol to minors, so please show your ID.)
Explaining why a mistake or failure occurred.
Used in retrospective reasoning, explaining the cause of a negative outcome (often self-critique).
Example: ้
ๅปใใฆใฏใใใชใใใใใใฃใจๆฉใๅฎถใๅบใในใใ ใฃใใ (Because you must not be late, I should have left home earlier.)
Frequency
Medium to High. The core phrase ‘ใฆใฏใใใชใ’ is common; adding ‘ใใ’ is frequently used to provide justification.
Difficulty
N3 (Intermediate)
Tag:
Example Sentences
Example #1
ใใใงใฟใใณใๅธใฃใฆใฏใใใชใใใใๅคใงๅธใฃใฆใใ ใใใ
Furigana: ใใ ใง ใใฐใ ใ ใใฃใฆใฏ ใใใชใใใใใใจ ใง ใใฃใฆ ใใ ใใใ
Romaji: Koko de tabako o sutte wa ikenai kara, soto de sutte kudasai.
English: Smoking is forbidden in this area, so please go outside to smoke.
Example #2
ๅคไธญใซๅคงใใช้ณใ็ซใฆใฆใฏใใใชใใใใ้ใใซใใฆใใ ใใใ
Furigana: ใใชใ ใซ ใใใใช ใใจ ใ ใใฆใฆใฏ ใใใชใใใใใใใใซ ใใฆ ใใ ใใใ
Romaji: Yonaka ni ookina oto o tatete wa ikenai kara, shizuka ni shite kudasai.
English: You must not make loud noises late at night, so please be quiet.
Example #3
่ฆชๅใชไบบใซๅใใคใใฆใฏใใใชใใใใๆญฃ็ดใซ่ฉฑใในใใ ใ
Furigana: ใใใใคใช ใฒใจ ใซ ใใ ใ ใคใใฆใฏ ใใใชใใใใใใใใใ ใซ ใฏใชใในใใ ใ
Romaji: Shinsetsu na hito ni uso o tsuite wa ikenai kara, shลjiki ni hanasu beki da.
English: Since lying to kind people is not allowed, you should speak honestly.
Example #4
ใในใไธญใซๆบๅธฏ้ป่ฉฑใไฝฟใฃใฆใฏใใใชใใใใ้ปๆบใๅใฃใฆใใใชใใใ
Furigana: ใในใ ใกใ
ใ ใซ ใใใใใงใใ ใ ใคใใฃใฆใฏ ใใใชใใใใใงใใใ ใ ใใฃใฆ ใใใชใใใ
Romaji: Tesuto chลซ ni keitai denwa o tsukatte wa ikenai kara, dengen o kitte okinasai.
English: Using mobile phones during the test is forbidden, so turn off the power.
Example #5
็ดๆใ็ ดใฃใฆใฏใใใชใใใใๅฟ
ใๅฎใใใใซใ
Furigana: ใใใใ ใ ใใถใฃใฆใฏ ใใใชใใใใใใชใใ ใพใใ ใใใซใ
Romaji: Yakusoku o yabutte wa ikenai kara, kanarazu mamoru yล ni.
English: You must not break a promise, so make sure to keep it.
Example #6
่ฒด้ๅใ็ฝฎใใฃใฑใชใใซใใฆใฏใใใชใใใใๅฟ
ใๆใกๆญฉใใพใใใใ
Furigana: ใใกใใใฒใ ใ ใใใฃใฑใชใ ใซ ใใฆใฏ ใใใชใใใใใใชใใ ใใกใใใใพใใใใ
Romaji: Kichลhin o okippanashi ni shite wa ikenai kara, kanarazu mochiarukimashล.
English: Because you must not leave valuables unattended, let’s make sure to carry them with us.
Example #7
ๅณๆธ้คจใง้ฃใน็ฉใ้ฃฒใฟ็ฉใๅใฃใฆใฏใใใชใใใใไผๆฉๅฎคใไฝฟใใพใใใใ
Furigana: ใจใใใใ ใง ใในใใฎ ใ ใฎใฟใใฎ ใ ใจใฃใฆใฏ ใใใชใใใใใใ
ใใใ ใใค ใ ใคใใใพใใใใ
Romaji: Toshokan de tabemono ya nomimono o totte wa ikenai kara, kyลซkei shitsu o tsukaimashล.
English: Since eating or drinking is not allowed in the library, we should use the break room.
Example #8
ๅฝผใฏๆชๆๅนดใ ใใใใ้
ใ้ฃฒใใงใฏใใใชใใใใใธใฅใผในใซใใชใใใ
Furigana: ใใ ใฏ ใฟใใใญใ ใ ใใใใใใ ใ ใฎใใงใฏ ใใใชใใใใใใ
ใผใ ใซ ใใชใใใ
Romaji: Kare wa miseinen da kara, osake o nonde wa ikenai kara, jลซsu ni shinasai.
English: Because he is a minor, he must not drink alcohol.
Example #9
ๅปไธใ่ตฐใฃใฆใฏใใใชใใใใใใฃใใๆญฉใใชใใใ
Furigana: ใใใ ใ ใฏใใฃใฆใฏ ใใใชใใใใใใฃใใ ใใใใชใใใ
Romaji: Rลka o hashitte wa ikenai kara, yukkuri arukinasai.
English: Since running in the hallways is dangerous, walk slowly.
Example #10
ๅไบบๆ
ๅ ฑใๆผใใใฆใฏใใใชใใใใ็บ่จใซๆฐใไปใใฆใใ ใใใ
Furigana: ใใใ ใใใใปใ ใ ใใใใฆใฏ ใใใชใใใใใฏใคใใ ใซ ใ ใ ใคใใฆ ใใ ใใใ
Romaji: Kojin jลhล o morashite wa ikenai kara, hatsugen ni ki o tsukete kudasai.
English: Because you must not reveal personal information, please be careful about what you say.
Notes & Nuances
๐ Important Points
The essential role of the particle ใฏ (wa).
The particle ใฏ emphasizes the prohibition, contrasting the prohibited action with what should be done. It functions similarly to ‘Vใฆใฏใใก/ใชใใชใ’.
Example: ๅญฆๆ กใงๆบๅธฏใใใใฃใฆใฏใใใชใใใใใญใใซใผใซใใพใใชใใใ
It always sets up a necessary consequence.
This structure is often followed by a strong instruction, command, or a statement of necessity, as the reason given (prohibition) requires an immediate consequential action.
Example: ๅฎฟ้กใๅฟใใฆใฏใใใชใใใใไปใใใใใชใใใ
‘ใใ’ softens the prohibition by providing a reason.
The reason (‘ใใ’) explains why the prohibition (‘ใฆใฏใใใชใ’) exists, linking the prohibition to a further conclusion (e.g., finding another route).
Example: ใใใฏ็ซใกๅ
ฅใ็ฆๆญขใ ใใใๅ
ฅใฃใฆใฏ ใใใชใใใใๅฅใซใผใใๆขใใใ
โ ๏ธ Common Mistakes
โ Vใฆใใใชใใใ (Vte ikenai kara)
โ
Vใฆใฏใ ใใ ใใ (Vte wa dame da kara)
While conveying a similar meaning, students sometimes forget the particle ใฏ, which is essential for the prohibition structure (Vใฆใฏ [ใใใชใ/ใ ใ]).
โ Using ‘ใฆใฏใใใชใใใ’ for simple obligation.
โ
ๅณๆธ้คจใงใฏ้ใใซใใในใใ ใใใ (Toshokan de wa shizuka ni suru beki da kara.)
Students sometimes overuse ‘ใฆใฏใใใชใ’ even when the rule can be expressed positively using ‘ในใ’ (should) or ‘ใชใใฆใฏใใใชใ’ (must). ‘ใฆใฏใใใชใใใ’ focuses strictly on prohibition.
โ ้จๅฑใซๅ
ฅใฃใฆใใใใใใๅพ
ใกใชใใใ(Mistake in logic/meaning)
โ
่จฑๅฏใๅพใๅพใงๅ
ฅใใ (Kyoka o eta ato de hairu.)
Confusing the prohibition form with the permission form ‘ใฆใใใ’ (may/is allowed). The ‘ใฏ’ particle signals restriction.
๐๏ธ Cultural Context
Politeness Level: Medium. ‘ใฆใฏใใใชใ’ is a direct expression of prohibition. Adding ‘ใใ’ makes it less of a harsh command and more of a justified explanation. For higher politeness, ‘Vใฆใฏใชใใพใใใใ’ or indirect phrases are used.
Social Situations: Appropriate for contexts involving rules (school, workplace, public signs) or when correcting a subordinate/child. Used less often toward a superior unless citing an external, non-negotiable regulation.
Regional Variations: The structure is standard Japanese. In Kansai, regional variations of the auxiliary verb might be heard, but ‘ใฆใฏใใใชใใใ’ is universally understood.
๐ Subtle Differences
Vใฆใฏใ ใใ ใใ (Vte wa dame da kara)
‘ใฆใฏใ ใ’ is generally perceived as slightly softer and often used by parents or teachers toward children. It implies ‘it’s no good’ rather than a strict legal prohibition.
When to use: When the prohibition is based on personal judgment or simple courtesy rather than a formal rule.
Vใในใใงใฏใชใใใ (Vru beki dewa nai kara)
‘ในใใงใฏใชใ’ means “should not” or “it is not appropriate to.” It implies moral or social obligation, whereas ‘ใฆใฏใใใชใ’ is a strict rule or command.
When to use: When expressing that an action is morally or socially incorrect, rather than strictly prohibited by law or rule.
Vใฆใฏใใใชใ (Vte wa ikenai – without ใใ)
The version without ‘ใใ’ is a straightforward command or statement of prohibition. Adding ‘ใใ’ shifts the focus from commanding to explaining/justifying the command.
When to use: Use ‘ใฆใฏใใใชใ’ for direct rules; use ‘ใฆใฏใใใชใใใ’ when the rule needs to be followed by a consequential action or explanation.
๐ Conjugation Notes
The structure requires the verb to be in the ใฆ-form. ใใใชใ is the negative form of the potential verb ใใ (from ใใ, obsolete), acting as a fixed expression equivalent to a negative i-adjective. Therefore, it changes to ใใใชใใฃใ in the past tense, e.g., Vใฆใฏใใใชใใฃใใใ.
๐ Pronunciation Tips
The particle ใฏ is always pronounced ‘wa’ in this context. There is a slight pause or stress before the ‘ใฏ’ to emphasize the action being forbidden.
๐ง Memory Tips
Think of it as: V-ing (Vใฆ) + Is Absolutely Forbidden (ใฏ ใใใชใ) + Because (ใใ). The ‘ใฏ’ is the barrier you cannot cross.
Other Grammar
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