Beatrice's letter is a recurring object in the Umineko no Naku Koro ni universe. The delivery of the letter signals the beginning of the race to solve the witch's epitaph. Maria receiving the letter from an unknown individual claiming to be Beatrice is the one fixed point in almost any given fragment, analogous to the Watanagashi Festival of Higurashi no Naku Koro ni. The letter is made of the official Ushiromiya stock and is sealed with the Head's ring, a symbol of its authenticity.
The head ring is a golden signet ring emblazoned with the One-Winged Eagle meant to symbolize headship of the Ushiromiya family. Up until the events of Umineko no Naku Koro ni, the ring was worn by Kinzo Ushiromiya. The ring is also used as a wax stamp as a sort of signature for stationary created by the family head. The ring's stamp is what lends authenticity to Beatrice's letters.
The head ring is used to represent the "territory lord" in Dawn of the Golden Witch; the person wearing the head ring has absolute control of Rokkenjima and all Games hosted therein. At the beginning of Dawn of the Golden Witch, the ring is worn by BATTLER, however its ownership is briefly transferred to Erika Furudo while BATTLER is trapped in a Logic Error.
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 as well as Kinzo's study. Only two sets of keys can open Kinzo's study: those held by Genji Ronoue and those held by Kinzo himself.
The scorpion charms are bracelets given to Battler and Jessica Ushiromiya by Maria. Jessica later gives hers to Natsuhi. Maria believes the charms keep people safe from Beatrice as scorpions are said to have the power to ward off evil.
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 Umineko no Naku Koro ni during the Rokkenjima massacre.