syukkin no ato, haizoku ga kimarimasita.

出勤 is a verbal noun (a noun that can also be used with する to make a verb).

• As a noun: 出勤 = going to work / reporting to work
• As a verb: 出勤する = to go to work

In this sentence, it is being used in a noun-like way, which is why it appears before の後.

Both are possible, but they are built differently.

• 出勤の後
  uses 出勤 as a noun
• 出勤した後
  uses 出勤する as a verb clause

So:

• 出勤の後 = after going to work / after reporting to work
• 出勤した後 = after having gone to work

The version with の can sound a little more concise or formal, especially in workplace or written contexts. Since 出勤 is a Sino-Japanese verbal noun, it works very naturally this way.

Because 後 behaves like a noun, and when one noun modifies another noun in Japanese, の is often used.

So the structure is:

• 出勤
  • の
    • 後
• literally: the after of reporting to work

This is the noun-modifying pattern.

Compare:

• 会議の後 = after the meeting
• 仕事の後 = after work
• 出勤の後 = after going to work

If you use a verb instead, you do not use の:

• 出勤した後
• 食べた後
• 帰った後

後 means after.

In this sentence, it marks that the second event happened after the first one:

1. 出勤
2. 配属が決まりました

So the timeline is:

• first: going to work / reporting to work
• later: the assignment was decided

Depending on context, 後 can mean:

• after
• afterward
• later
• following

配属 means something like:

• assignment
• placement
• posting
• being assigned to a department/team/location

It is often used in company, military, or institutional contexts.

For example, it can refer to being assigned to:

• a department
• a branch office
• a team
• a section

So 配属が決まる is a very common expression meaning one’s placement/assignment gets decided.

Because 配属 is the thing that was decided.

The verb here is 決まる, which is an intransitive verb meaning:

• to be decided
• to be settled

With 決まる, the thing that gets decided is usually marked by が.

So:

• 配属が決まりました
• literally: the assignment got decided

This is different from English, where we often say they decided my assignment. Japanese often focuses on the result itself rather than on who made the decision.

This is a very important distinction.

• 決める = to decide something (transitive)
• 決まる = to be decided / to get decided (intransitive)

So:

• 会社が配属を決めました
  = The company decided the assignment.

• 配属が決まりました
  = The assignment was decided.

In your sentence, the speaker is not focusing on who made the decision. The focus is on the fact that the assignment became settled.

This is extremely common in Japanese.

No. It is not passive.

It is the polite past form of 決まる:

• dictionary form: 決まる
• polite present: 決まります
• polite past: 決まりました

A true passive form would come from 決める, for example:

• 配属が決められました

But that is a different structure. Your sentence uses the intransitive verb 決まる, not the passive.

This matters because Japanese often prefers intransitive expressions where English might use passive.

Japanese often leaves the agent unstated when it is obvious, unimportant, or better left vague.

In this case, the person or organization making the decision is probably something like:

• the company
• HR
• management
• the school/institution

But the sentence does not say, because the important information is simply that the assignment was decided.

This omission is very natural in Japanese.

Because the speaker is reporting a completed event in a polite style.

• 決まる = plain dictionary form
• 決まった = plain past
• 決まりました = polite past

So the sentence is appropriate in:

• normal polite conversation
• workplace speech
• written reports
• formal narration

It sounds more neutral and professional than the plain form.

They are very close in meaning.

• 出勤の後 = after going to work
• 出勤後 = after reporting to work / post-attendance

出勤後 is a more compact, slightly more formal or written-style expression.
出勤の後 is a bit more explicitly structured and may feel a little easier for learners to parse.

Both can be natural depending on context.

The comma helps separate the time phrase from the main statement.

So the structure is:

• 出勤の後、 = after going to work,
• 配属が決まりました。 = the assignment was decided.

This kind of comma is very common when a sentence begins with a time or condition phrase. It makes the sentence easier to read, though punctuation in Japanese can sometimes be flexible.

Yes. The sentence follows a very common Japanese pattern:

• time expression
• subject/topic
• verb

So here:

1. 出勤の後 = after going to work
2. 配属が = the assignment
3. 決まりました = was decided

Japanese often places background information such as time, place, or context near the beginning, and puts the main verb at the end.

Yes, that is a very reasonable nuance.

Depending on context, 出勤の後 could mean:

• after I showed up for work
• after I started coming in
• after reporting for duty/work

And 配属が決まりました suggests that the assignment or placement was settled afterward.

So the sentence can carry the sense that the placement was not known in advance, and was determined only after that point.