From the VHC~A1 [Definitive Document] Part I - Introduction, 22 May 2020, in which Peter Sharrock wrote:

Vanishing House Catalogue (VHC) is a process designed for the organisation and classification of my various items, tasks, and presentations. Vanishing House takes its name from the place in North Wales where we played as children. VHC is organised in accordance with the current edition of its definitive document (VHC~A1) which was first drafted in 1985 and has been revised many times since.

VHC began in the early 1970s with several boxes full of stuff. Over the years its organisation evolved and was given different names. In some places, some of those old names and catalogue numbers have remained visible. VHC is not a complete record. Items produced or presented through VHC are routinely positioned with a VHC index number for the purposes of a project (such as vhc.5mc.wsp.2020_04_01) but when that project is finished then its registers, inventories and distribution lists will usually be deleted. So, although one might find an item inscribed with a catalogue number, its original index may no longer exist. For example, an authorisation might say an item had been the third of ten prints, but it may no longer be possible to determine whether those other nine prints were distributed or destroyed.

This introduction continues separately and in various places through occasional notes labelled with the date of their creation (for example VHC.2020_02_12) but those notes are usually not listed in registers or indexes - and most, if not archived, will eventually be deleted.