[RPG] Is a puzzle box considered locked


As part of some treasure the party I am in found, we found a puzzle box. I am a wizard, and I wanted to use the spell Knock to open it. Knock says:

Choose an object that you can see within range. The object can be a door, a box, a chest, a set of Manacles, a padlock, or another object
that contains a mundane or magical means that prevents access.

A target that is held shut by a mundane lock or that is stuck or
barred becomes unlocked, unstuck, or unbarred. If the object has
multiple locks, only one of them is unlocked.

(emphasis mine). None of my party rolled high enough on an Investigation check to manage to open the box, and I said I wanted to cast Knock to open it. My rationale was that each step of the puzzle was a lock, and if I casted Knock enough times, it would open the puzzle box.

However, my DM said that the puzzle box isn't technically "locked". My thought was that since Knock will unstick or unbar doors, the item doesn't need to be technically locked with a physical lock, it just needs to prevent us from opening it. I did not want to fight about it, so I dropped it, but I was curious if there is an official ruling. However, I did read this post and I'm not sure if the top answer agrees or disagrees with my specific situation.

So, can Knock open a puzzle box? If so, would it take one casting total, or one casting for each step of the puzzle?

Update: I really appreciate the discussion on various types of puzzle boxes and I think it is really stimulating. HOWEVER, I think I was not specific enough with my description of this puzzle box. The puzzle box was described to us with a lot of clarifications: it is similar to a Japanese puzzle box (himitsu-bako) where it contains switches/levers/ moving pieces of whatever type. Moving one piece allows the next piece to be moved, and so on, until presumably the last piece, which blocks the lid from opening, is moved.

Best Answer

"A mundane or magical means of preventing access"

The rationale your DM used was that the puzzle box is not 'locked'. However, nowhere in the description of Knock does it specifically say that it works on locks.

This is because, as per the quoted section, it undoes any means (mundane or magical) of preventing access, and the fact that it later mentions only 'unlocked, unstuck, or unbarred' is clearly not intended to be limiting, since it later only references unlocking. If it were providing limitations, you would have to rule that a door with both a bar and a lock would be immune to Knock, since the last sentence only addresses locks, which would be rather silly.

It also seems that it would only require one casting to unlock the entire puzzle box, large interconnected system or not. After all, you don't need to cast the spell for each tumbler in a lock, and even extraordinarily complicated locks (some of them get truly devilish) can be undone easily with this spell. Since complexity and number of moving parts isn't an issue, Knock would therefore have to undo the entire puzzle box at once.

Now, if you had a puzzle box with 6 sides, and each one had a separate mechanism, or if there were multiple boxes inside each other, it would require multiple castings, but it does not sound like this resembles your situation.