Breakdown of kaze ga tsuyoi hi wa, sentakumono ga hayaku kawaku.
Questions & Answers about kaze ga tsuyoi hi wa, sentakumono ga hayaku kawaku.
It is a clause + noun pattern:
- 風が強い = the wind is strong
- 日 = day
So 風が強い日 literally means a day when the wind is strong.
A key point for English speakers: Japanese puts the describing clause before the noun. There is no word like when, that, or which here.
So the structure is:
- [風が強い] 日
- [the wind is strong] day
This is one of the most common Japanese patterns for making expressions like the person who came, the book I bought, the day when it rained, etc.
Here, 風 is the subject of the small clause 風が強い.
- 風が強い = the wind is strong
Using が is the normal, neutral choice inside this kind of noun-modifying clause.
If you used は instead, it would sound much more marked or contrastive, and in this sentence it would not be the natural way to say it.
So for a learner, the safest takeaway is:
- X が adjective/noun/verb + noun is a very common pattern
- 風が強い日 = a day when the wind is strong
