Re5 is the correct method because White's king is cut off from the pawn, White will have to spend a lot of time activating his rook, and by that time the black king will be able to get over to the queenside.
Che5 é o método correcto porque o rei branco está cortado do peón pasado e o branco terá que gastar moitos tempos para activar a súa torre e nese momento o rei negro poderá alcanzar o flanco de dama.