Ich setze mich auf den Stuhl.

I sit down on the chair.

Breakdown of Ich setze mich auf den Stuhl.

• ich: I
• der Stuhl: the chair
• den: the
• auf: on
• sich setzen: to sit down

Questions & Answers about Ich setze mich auf den Stuhl.

Why is mich used in this sentence instead of omitting it?

Because setzen is used reflexively here: you’re seating yourself. German reflexive verbs require a reflexive pronoun (in this case mich, the first-person singular accusative). If you dropped mich, the verb would need a direct object (and the meaning would change: “I set something on the chair”).

Why is the preposition auf followed by den (accusative) instead of dem (dative)?

Auf is a two-way (Wechsel-) preposition. With movement toward a goal (answering “where to?”) it takes the accusative. Here you move onto the chair, so it’s auf den Stuhl. If you were already sitting (no movement, “where?”), you’d use dative: Ich sitze auf dem Stuhl.

What is the difference between Ich setze mich auf den Stuhl and Ich sitze auf dem Stuhl?

Ich setze mich auf den Stuhl describes the action of sitting down (a change of position).
Ich sitze auf dem Stuhl describes the resulting state of sitting (you are already sitting).

How would you express “I sat down on the chair” in German using the present perfect tense?

You’d say Ich habe mich auf den Stuhl gesetzt.
• Use haben as the auxiliary for reflexive/transitive verbs.
• The past participle is gesetzt.

Could I replace setzen with stellen or legen here?

No.
• stellen means “to place (something upright),” always transitive and non-reflexive (e.g., Ich stelle den Stuhl in die Ecke).
• legen means “to lay (something down flat),” also transitive.
To seat yourself you must use the reflexive sich setzen.

What’s the difference between sich setzen and sich hinsetzen?

Both mean “to sit down,” but hinsetzen is a separable verb adding hin-, which emphasizes the direction “away from the speaker” or simply feels more colloquial.
In the present tense: Ich setze mich (hin) auf den Stuhl (the hin moves to the end).

Why does the finite verb setze appear in the second position and the reflexive pronoun mich right after it?

German main clauses follow the V2 (verb-second) rule: the finite verb is always the second element. After the verb, you list your objects/pronouns. Reflexive pronouns typically come before longer phrases (like auf den Stuhl), so the order is:

1. Ich (subject)
2. setze (finite verb)
3. mich (reflexive pronoun)
4. auf den Stuhl (prepositional object).