The Schroedinger's Box (シュレディンガーの箱 Shuredingā no Hako ) is variously referred to as a box with a truth or a cat inside, based on the famous Schroedinger's Cat thought experiment on what occurs in the wavefunction collapse of quantum probabilities. The experiment presents a cat in a box with a radioactive substance and a lethal gas that will be released when the radiation detector is triggered. At any given moment, the cat's probable states, alive or dead, are superposed in truth, and only when the box is opened to reveal the cat will one state become true.
The universe of Umineko no Naku Koro ni assumes a combination of 'many-worlds' and 'relational' interpretations; the probability waveform collapses at each observer's observation, and the superposed states decohere into consistent histories. Only one consistent history can be experienced by each observer, but in the Meta-World, they can all be viewed. The game held in Meta dramatizes the struggle between consistent histories and the re-coherence of opposing observers into one 'true' observation.