Learn Hardcore Japanese: kinou ha eki made arukimasita. - I walked to the station yesterday.

In Japanese, time expressions like 昨日 often become the topic of the sentence, so you use は. This is called a temporal topic marker—literally “As for yesterday…,” setting the time frame. You could use に to mark a point in time (昨日に), but it’s much less common when you want to make the time the topic.

Why is there no subject like “I” in the sentence?

Japanese commonly drops subjects when they’re clear from context. Because walking to the station is a natural action, the speaker and listener usually know who’s doing it. If you need to be explicit, you can add:
• 私は昨日は駅まで歩きました
(As for me, I walked to the station yesterday.)
But in most cases it’s unnecessary.

What does 駅まで mean? How does まで function here?

• 駅 is “station.”
• まで means “until” or “up to.”
Together 駅まで means “as far as the station” or “to the station.” In movement verbs, まで marks the endpoint of that movement.

Could I use に instead of まで to say “to the station”? What’s the difference?

Yes. 駅に歩きました is grammatically possible and means “walked to the station.”
Difference in nuance:
• に simply marks the destination.
• まで emphasizes the limit or endpoint of the action (“all the way to that point”).
In many cases they’re interchangeable for physical movement, but まで adds that subtle “up to” flavor.

What tense and politeness level is 歩きました?

• It’s the past tense of 歩く (to walk).
• It uses the –ます form, which is polite.
So 歩きました means “walked” in a polite style.

How would I say the same sentence in casual (plain) form?

You change 歩きました to the plain past 歩いた.
The sentence becomes:
昨日は駅まで歩いた
This is how you’d say it among friends or in informal writing.

Why is the verb at the very end of the sentence, instead of after the subject like in English?

Japanese follows Subject-Object-Verb (SOV) word order. Verbs (and verb phrases) always come last. Particles mark each noun’s role, so you can move phrases around for emphasis, but the verb typically stays at the end.

Why can’t I say 昨日に駅まで歩きました?

Using に with 昨日 marks a specific time point, but if you also want to make it a topic (to contrast or emphasize), you use は. Saying 昨日に here sounds unnatural because you’d lose that topical nuance. Stick with 昨日は when setting the time frame as the topic.