Objects in Umineko no Naku Koro ni

Master keys
The master keys are a group of keys that can open virtually any door on Rokkenjima. The master keys are held only by servants and play an important role in several closed-room mysteries. The only doors that the master keys cannot unlock are those to the chapel on Rokkenjima.

Scorpion charm
The scorpion charm is a bracelet given to Natsuhi by Jessica.

Winchester rifles
The Winchester rifles are four Winchester Model 1894 rifles owned by Kinzo Ushiromiya, all of which have been sawed off and outfitted with enlarged lever loops in order to resemble the Mare's Leg rifle from Wanted Dead or Alive. The rifles play an important part in the story of during the Rokkenjima massacre.

In the meta-world, the rifles are personified as the Chiester Sisters.