こそ〜が / こそ〜けれど

こそ … が grants one point and then turns to a contrasting one: "X, granted, but …", "it's true that X, but …". こそ goes straight after the noun being conceded, and the clause ends in が or けれど before the contrast.

The conceded noun is usually one feature of the subject – its size, its price, its shape – set against another feature that matters more.

Verbs and adjectives

こそ can't go straight after a verb or a predicate adjective. A verb goes into the ます-stem and takes こそする; a noun or a な-adjective as the predicate takes でこそある.

• × わかるこそするが → わかりこそするが

Not the same as からこそ

からこそ is "precisely because", and ことし今年こそ is "this year for sure". Both put こそ in a sentence that may go on with が, but neither concedes anything. In this pattern the part with こそ is the weaker half of the sentence; the point is what follows が.

Register

The pattern belongs to writing and careful speech: reviews, essays, reports. In conversation, は … けど carries the same contrast with less weight: ねだん値段はたかい高いけど、おいしい.