How do locks for shoe lockers in Sentōs work?

Question

(Please move this question to the appropriate exchange site if it is not this one; I originally posted this here, and a comment suggested that I move it here.)

In Danganronpa it appears that the lock at 9:27 in this video has a weird shape, and I cannot figure out how it might work. Using Google, it appears that these are locks for shoe lockers in Sentōs, but I haven't been able to find a picture showing how they work.

A comment on the original place I put this question pointed me to this website, which says "The wooden key was interesting as it had grooves in it. If the pattern of the grooves match the pins in the lock then the key will go all the way down and trip the catch on the lock." However, this seems a little suspicious because then it looks like you could open any lock by using a small stick.

After some more googling I found this auction which has pictures of inside of the lock (and also pictures of the key, which are different from those in the game; I am now guessing that the key shape in the game probably does not exist, but only because I cannot come up with a lock mechanism for it). It does not explain how it works, though, and I am still interested in this.

How do they work? More specifically,

1. Is the picture of the lock in the video realistic?

2. Is the description from that website accurate, and if not then how does it work?

Answer 1

The key in the game is not a realistic representation of keys used in traditional Japanese shoe lockers - it has lateral groves besides normal lengthwise groves used in these locks. They are usually low-security locks that act on principle similar to warded locks (only fixed obstructions blocking a mismatching key; a key that is significantly slimmer will just work) - and similarly, easy to bypass. Possibly there exist more secure variants; I haven't encountered any.

A lock like in the video would be fairly easy to implement as a variant of a dimple lock - a lock where the key has holes on the flat surface and engages the tumblers with its sides instead of edges.

Instead of drill holes, groves can be used to engage the tumblers at various locations to various depth; to avoid necessity of turning, and thanks to the size of the key, the tumblers could be considerably bigger and act directly as the latches on the door. Still, this sort of key, made of wood, would sooner or later get dented by the tumblers, failing eventually. So, a lock like this is possible, is not very practical, and it's highly dubious if it's used in reality.