Fencer, your idea of "Would you dare to win Espionage by capturing opponent's base without revealing it by a spy?" is good but rather easy. Just capture it with a sab! Perhaps modify the achievement to "Would you dare to win Espionage by capturing the opponent's base with a 4 or 5 without revealing it with a spy?"
(gem) Hvis du vil vide mere om nogle spil, kan du tjekke under link sektionen og se om du finder nogle interessante links der. (pauloaguia) (vis alle tips)