Learn Hardcore Korean: i gaeksireun chekeu-inhal ttae hotel gyujeongsang geumyeon guyeoginji hwaginhaesseoyo. - I checked at check-in whether this room is a non-smoking area according to hotel rules.

-은/는 marks a topic: 이 객실은 = “As for this room…”. The (implicit) subject of 확인했어요 is “I/we,” which is omitted.
If you wrote 이 객실이 in this exact position, it would wrongly make “this room” the subject of “checked,” which doesn’t make sense.
You can, however, use 이 객실이 inside the embedded clause: 체크인할 때 이 객실이 호텔 규정상 금연 구역인지 확인했어요.

Why is it 체크인할 때 and not 체크인했을 때?

-할 때 can describe a general time or routine (“when checking in”), and Koreans often use it even for past events.
-했을 때 points specifically to a past occasion (“when I/we checked in [that time]”).
Both work here; -할 때 sounds a bit more general/neutral, -했을 때 more event-specific.

What does 호텔 규정상 mean, and how is -상 used?

-상 after a Sino-Korean noun means “in terms of / according to / from the standpoint of.” So 호텔 규정상 ≈ “according to hotel rules/policy.”
Common parallels: 법률상 (legally), 계약상 (contractually), 이론상 (theoretically), 원칙상 (in principle).
Synonyms: 호텔 규정에 따르면/따라. -상 sounds a bit formal and compact.
Spacing: write 규정상 as one word (not 규정 상).

Does 호텔 규정상 modify the noun or the whole clause?

It modifies the whole clause “(it) is a non-smoking area,” not the noun itself. Read it as: “whether, according to hotel rules, it is a non-smoking area.” You could make this explicit: 호텔 규정상 이 객실이 금연 구역인지…

Why 금연 구역인지 and not 금연 구역인가?

-인지 is the indirect-question ending used before verbs like 확인하다, 알다, 모르다, 궁금하다. It means “whether/if.”
For a noun + 이다, you attach -인지: 금연 구역(이)다 → 금연 구역인지.
-인가 is for direct questions (e.g., …인가요?) and is incorrect before 확인했어요.

Is 금연 구역 the best choice here, or should it be 금연실? Also, what about 객실 vs 방?

금연 구역 = “non-smoking area/zone” (general spaces like lobbies, floors, property-wide areas).
금연실 = “non-smoking room” (a specific hotel room category). If you literally mean the room type, 금연실인지 is more precise.
객실 is the formal/hotel word for “guest room”; 방 is the everyday word “room.” In a hotel context, 객실 is more natural/formal.

Can I just say 금연인지 instead of 금연 구역인지?

Yes. 금연인지 (“whether it’s non-smoking”) is common and natural. If you want maximum clarity that you mean the room category, 금연실인지 is the most specific.

Why is there no object marker after the clause (no …인지를)? What is the object of 확인했어요?

Verbs like 확인하다/알다/모르다 take a content clause directly as their object, so …인지 확인했어요 is complete and natural.
If you want an explicit object noun, you can say:
- …인지 여부를 확인했어요 (formal)
- …인지 확인(을) 했어요 (nominalized “confirmation” + object marker)
Don’t attach 를 directly to …인지 in modern usage.

What are the register/nuance differences among 확인했어요, 확인했습니다, 확인해 봤어요, and 확인받았어요?

확인했어요: neutral polite (“I checked/confirmed”).
확인했습니다: formal polite (service situations, writing).
확인해 봤어요: “I tried checking / I went and checked,” a bit more exploratory.
확인받았어요: “I received confirmation (from someone),” e.g., 직원에게 확인받았어요. Focuses on getting confirmation from a source.
If staff did it for you: 직원분이 확인해 줬어요 (“checked for me”) is also common.

Can I change the word order?

Yes. Natural options include:

체크인할 때 이 객실이 호텔 규정상 금연 구역인지 확인했어요.
이 객실은 호텔 규정상 금연 구역인지 체크인할 때 확인했어요. Keep the embedded clause right before 확인했어요 for clarity. Using 이 객실이 is fine inside the …인지 clause, but not as the main subject of 확인했어요.

Is the 이 in 이 객실은 the subject particle?

No. Here 이 is the demonstrative determiner “this.” The subject particle -이 would attach to a noun (e.g., 객실이). In 이 객실은, you have determiner 이 + noun 객실 + topic marker -은.

Any pronunciation tips for tricky spots?

객실은: often sounds like “객씨른” due to consonant strengthening at 시.
금연: commonly pronounced close to “그면” (the y-glide makes ㅕ sound like ‘yeo’ merging to ‘myeon’).
할 때: pronounced smoothly as “할때.” These are normal connected-speech effects; you’ll hear them in natural conversation.

Are the spacings here correct? I’ve seen 금연구역 without a space, too.

규정상: write as one word (not 규정 상).
금연 구역 vs 금연구역: both appear; the single-word compound 금연구역 is very common on signs. Either is acceptable in practice.
체크인할: no space between 체크인 and 할 because 체크인하다 behaves like a verb.

Why 때 and not 동안?

-때 = “at the time when/that,” anchoring an event point: 체크인할 때 (“when checking in”).
-동안 = “for (a duration),” which is odd for a brief event like check-in. 체크인하는 동안 would mean “during the whole time we were in the process of checking in,” which isn’t needed here.

Could I use -는지 or 여부 instead of -인지?

Use -인지 with nouns (from 이다): 금연 구역인지, 금연실인지.
Use -는지 with verbs/adjectives: 조용한지 (adj), 문이 닫혔는지 (verb).
여부 is a formal noun meaning “whether or not”: 금연 구역인지 여부를 확인했습니다. This is common in written/formal contexts.

Can I omit 호텔 규정상? What changes?

Yes: 이 객실은 체크인할 때 금연 구역인지 확인했어요. Without it, you’re simply saying you checked if it was non-smoking. With 호텔 규정상, you add the nuance “as per hotel policy,” not just signage or common sense.