瓮中之鳖

瓮中之鳖 [wèng zhōng zhī biē]

1. ■ (be cornered like) a turtle in a jar; a captive turtle in an earthen jar; (like) a rat in a hole; a sitting duck; a turtle in the jar-bottled up; inescapable situation; trapped:

瓮中之鳖， 手到拿来。 A turtle in a jar is certainly caught within the reach.