から

から marks origin — the starting point of a motion, a time range, or a causal chain.

Spatial origin: 東京から京都まで — "from Tokyo to Kyoto." Temporal origin: 九時から始まる — "starts from nine." Cause: 寒いから家にいる — "I'm staying home because it's cold." When attached to a clause to mark cause, から sits at the end of the clause and the reason clause comes first.

から (because) vs ので (because): both express cause. から is more subjective and conversational — it presents the speaker's reasoning. ので is more objective and softer, often preferred when the speaker is asking for understanding or making a request: 寒いので、窓を閉めてもいいですか ("It's cold, so could I close the window?"). Beginners should default to から; ので is a polish layer.