Beatrice's letter

Beatrice's letter is a recurring object in the 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. The letter is made of the official Ushiromiya stock and is sealed with the Head's ring, a symbol of its authenticity.