χεροῖν

From LSJ

ἐν οἰκίᾳ τυφλῶν καὶ ὁ νυκτάλωψ ὀξυδερκήςeven the day-blind is sharp-eyed in a blind house | among the blind, the one-eyed man is king

Source

French (Bailly abrégé)

gén. et dat. duel de χείρ.

Russian (Dvoretsky)

χεροῖν: gen. и dat. dual. к χείρ.