Learn Hardcore Dutch: Anna blijft thuis; Tom daarentegen gaat naar het stadion. - Anna stays home; Tom, on the other hand, is going to the stadium.

daarentegen is a conjunctive adverb meaning “on the other hand” or “in contrast.” It connects two independent clauses and highlights the contrast between Anna (who stays home) and Tom (who goes to the stadium).

Why is there a semicolon between the clauses instead of a comma or a period?

The semicolon (puntkomma) links two closely related independent clauses more tightly than a period would, without the full stop, and it’s stronger than a comma alone. You could use a period:
Anna blijft thuis. Tom daarentegen gaat naar het stadion.
but the semicolon shows the direct contrast more elegantly. A comma would be incorrect here because each clause is a full sentence on its own.

Why does the word order change after daarentegen?

In Dutch, most adverbs or adverbial expressions placed at the beginning of a clause trigger inversion: the finite verb comes directly after them. So after daarentegen, the subject Tom follows the verb gaat, producing Tom daarentegen gaat… → inverted to daarentegen gaat Tom…. In your example the writer chose to keep Tom in front for clarity but still inverts gaat:
Tom daarentegen gaat naar het stadion.

Could we use maar instead of daarentegen here?

Yes, maar (“but”) also expresses contrast:
Anna blijft thuis, maar Tom gaat naar het stadion.
However, daarentegen is a bit more formal and emphasizes the opposition more strongly. With maar, you’d typically use a comma and no inversion: maar Tom gaat… instead of daarentegen gaat Tom….

Why do we say het stadion? Could you omit the article?

Most location nouns in Dutch require a definite or indefinite article. Stadion is a neuter noun, so its definite article is het. You cannot say naar stadion; it must be naar het stadion unless you specify a different article (e.g. naar een stadion for “to a stadium”).

Why is the verb blijft used for Anna rather than “is” (is) or another verb?

In Dutch, blijven means both “to stay” (intransitive) and “to remain” (linking verb). Here Anna blijft thuis literally means “Anna stays at home.” Using is thuis (“is at home”) is also possible but slightly less dynamic: blijven stresses that she stays put rather than just her location.

Is there any special rule for spacing around the semicolon in Dutch?

No. In Dutch typography you write a semicolon without a space before it and with a single space after:
Anna blijft thuis; Tom daarentegen…
This matches English punctuation rules.