The Anchor Chain is a device that binds The Library to this dimension. According to Judson, the power level required to sever the Chain is proportional to the extent of the Library, which in turn expands automatically to meet the Librarian's storage needs. Thus when, in 2014, the First Librarian sought to take this drastic step, he needed the assistance and power of the First Guardian to manage the task successfully.
The Library cannot be accessed from a fixed place or dimension unless bound to said realm by the Anchor Chain. The Library at that point exists solely in its own, inaccessible, pocket dimension.
This means that, until the Chain is reattached:
- No ordinary creature can enter the Library, not even a Librarian.
- The Back Door and similar devices will not be able to teleport things to the Library.
- Every Artifact housed inside the Library, excluding non-magical books, will be inaccessible.
Reattaching the Chain
Powerful enough magic can be used to reattach the Anchor Chain. The Librarians did so using:
- The Back Door
- The Libris Fabula
- The Wireless Power Transmitters
- An Advanced Learning Buddy app made by Morgan Le Fay
- As of "And the Loom of Fate" the Library is bound to the Annex.
- Judson (and probably any other Librarian) can break the chain with magic if they feel that the Library is in danger;
- The Annex was mostly unaffected by a broken Anchor Chain, as it is not a part of the Library itself;
- After the Serpent Brotherhood invaded The Library for the Crown of King Arthur, Judson and Charlene broke the seal anchoring the Library to the Metropolitan Public Library and closing it off until the end of Season 1.
- Shortly after the Chain is broken, the Library will literally fold itself like paper. If the living beings inside it do not manage to get to the door, they will be crushed.