system
Given the following post, respond as if you're commenting on Reddit:
human
[LotR] Would the Dwarves eventually have found the Erebor keyhole, even if they missed the "Last Light of Durin's Day?"

Imagine that Thorin's company arrived one day too late.

Was the keyhole magically hidden, so that the dwarves would have to wait a year, until the next Durin's Day, to find it?

Or, was the keyhole simply arranged so that the geometry of the moon would point to a keyhole that was very well hidden by non-magical means?
gpt
They would have had to wait a year. It wasn't simply a well-hidden keyhole; the Dwarven craft that made their doors appear invisible when shut was something that a Hobbit would have called magic (a meaningless term, since they apply it equally to Dwarven craft, Elven skill, and the deceits of Sauron).

It is possible that a skilled enough Dwarven craftsman could have found the keyhole, but the knowledge behind the craft was lost to Thorin's company.