Learn Hardcore Japanese: tentyou ha setumeisezu, kaigi wo tyuusisimasita. - The manager canceled the meeting without giving an explanation.

は marks the topic: “as for the manager…”. It presents the manager as known/given information and frames what follows as a comment about that topic.
Using が (as in 店長が説明せず…) would spotlight the manager as the grammatical subject and often implies contrast or answers “who did it?” (It was the manager who…).
In neutral narration, 店長は is more natural; 店長が is used when identifying or emphasizing the doer.

How do you read 店長 and what does it usually refer to?

Reading: てんちょう (tenchō)
It means the manager of a store, shop, or branch (e.g., the person in charge of a shop floor or restaurant), not a corporate “general manager.”

What does 説明せず mean, and why not 説明しないで?

Both express “without explaining.”
V-ず (here 説明せず) is a more formal/literary way to say “without doing.”
V-ないで (e.g., 説明しないで) is more common in speech and casual writing.
Meaning is the same; the choice is mostly about register.

How is せず formed from する? How do I make this form for other verbs?

It’s the classical negative connective V-ず (“without doing”).
For する, the form is irregular: せず (not “しず”).
Patterns:
- Ichidan (る-drop) verbs: 食べる → 食べず
- Godan verbs: negative stem + ず: 行く → 行かず, 話す → 話さず
- Irregular: する → せず, 来る → こず
Examples: 朝ごはんを食べずに出かけた。 / 理由を言わず、帰った。

Is 説明をせず also correct?

Yes. With する-verbs you can include を: 説明せず and 説明をせず are both acceptable. Without を is lighter and more common; with を can feel a bit heavier/emphatic.

Should it be 説明せず or 説明せずに? What’s the difference?

Both are fine:
- V-ず、… is a formal connective (“…and not doing X, …”).
- V-ずに、… explicitly marks “without doing X, …” and is very common.
Nuance is minimal; ずに sounds slightly more general-purpose in speech.

Can I use 説明しないで instead? Any nuance difference?

You can: 店長は説明しないで、会議を中止しました。

しないで is more conversational.
All three—せず, せずに, しないで—work. Choose based on formality.

Why is there no particle after 説明? Shouldn’t there be を or に?

説明する is a する-verb; in 説明せず the する part is in the ず form and connects directly to the next clause.
If you want to specify target or content, add phrases before せず, e.g.:
- 誰にも説明せず (without explaining to anyone)
- 理由を説明せず (without explaining the reason)
- 状況について説明せず (without explaining about the situation)

What does 会議を中止しました tell me about agency? How is it different from 会議が中止になりました?

会議を中止しました = an agent (here, the manager) actively canceled the meeting (transitive).
会議が中止になりました = the meeting ended up canceled (intransitive/result state), de-emphasizing who canceled it.
Use を中止した when you want to assign responsibility; が中止になった when you want to report the outcome.

Is 会議を中止にしました also possible? How does it differ from 中止しました?

中止にする means “to make/decide to cancel.” It emphasizes the decision-making act.
会議を中止にしました is fine and slightly highlights the “make it canceled” nuance.
会議を中止しました is the straightforward “canceled the meeting.”

What’s the difference between 中止, 延期, and 取り消し／キャンセル?

中止: cancel/terminate (it will not happen).
延期: postpone (it will happen later).
取り消し／キャンセル: cancel in the sense of revoking an application/order/reservation; context can overlap, but for events/meetings, 中止 or 延期 is standard.

Is it okay that 説明せず is plain form while 中止しました is polite?

Yes. Subordinate/preceding clauses are typically in plain form even when the main clause is polite. This style is natural and very common.

Is the comma 、 after 説明せず necessary?

It’s optional but improves readability. You can write 説明せず会議を中止しました; the meaning doesn’t change.

Can I move 説明せず later in the sentence or end the sentence with it?

The V-ず clause normally precedes the main action: 説明せず、会議を中止しました is the natural order.
You can use V-ないで if you want different placement: 店長は、説明しないで会議を中止しました。
Don’t end a sentence with …せず。 It needs a following main clause.

Does 説明せず carry any nuance beyond “without explaining”?

It can sound a bit curt or critical, implying “(just) went ahead without explaining.” To emphasize that nuance, 説明もせず (“without even explaining”) is common.

Are there set-phrase alternatives to 説明せず?

Yes, common options:

説明もなく (without so much as an explanation)
説明なしに (without explanation)
説明をしないまま (ended up not explaining and…) They vary slightly in tone, but all fit this context.

Why does 会議 take を?

Because 中止する is a transitive する-verb that takes a direct object. The thing being canceled (the meeting) takes を: 会議を中止する.

How would I make the sentence more casual or more formal?

More casual: 店長は説明しないで、会議を中止した。
More formal/businesslike: 店長は説明もなく、会議を中止いたしました。 or passive/result style 会議は説明もなく中止となりました。