Herbert Weir Smyth, A Greek Grammar for Colleges

a. ἄν is placed early in a sentence which contains a subordinate clause, in order to direct attention to the character of the construction: ““δοκοῦμεν δ᾽ ἄν μοι ταύτῃ προσποιούμενοι προσβαλεῖν ἐρημοτέρῳ ἂν τῷ ὄρει χρῆσθαι” if we should make a feint attack here it seems to me we should find the mountain to have fewer defenders” X. A. 4.6.13.

b. For rhetorical emphasis ἄν is added to give prominence to particular words: τίς γὰρ τοιαῦτ᾽ ἂν οὐκ ἂν ὀργίζοιτ᾽ ἔπη κλύων; and who would not be angered upon hearing such words? S. O. T. 339, πῶς ἂν οὐκ ἂν ἐν δίκῃ θάνοιμ᾽ ἄν; how should I not justly die? S. fr. 673.