When you "z"ap a Wand of Knocking, you will be able to direct a beam in any of the eight directions. Any doors in a direct row with the beam will be unlocked, assuming the wand is uncursed or blessed. If a locked door is unlocked with a Wand of Knocking, the following message will be produced: "You hear a knocking sound. You barely hear a clicking sound!". If an unlocked or open door is hit by the Wand of Knocking, the following message will be produced: "You hear a knocking sound. The lock of the door clicks several times."