Japanese
And here you got Japanese boxes. :)
Usually they don't have keys, but I guess there's some exceptions.
This was (I think) the first box with this mech. I acually had the idea but never built it. (Before this) The minus is that you can take out the pieces. This is made by joshualegotransform. <- Click for his channel.
This is my verision of the Japanese box on the top. As you can see it's a lot smaller, and you can't take out any piece.
This is the smallest verision so far of that box. It's 6 by 4, and 2 1/3 bricks in height.
This is that Japanese lego puzzle box you've seen above, but instead of 1 "lap", it's 2. This is the update though, cuse it looks better. And yes, the nail is fake, but I think the box is the main focus here. ;)
Well... here's another kind of Japanese box, for a change.
Here's a more Japanese likely box. Most of a prototype to test the mech.
Here's maybe the most Japanese box like lego puzzle box. (Yet) It's a prototype, cuse I wanted to fix some things, but now it's destroyed.
Here's the same type of box like the first one, but with a little different design, which change the mech a little. Therefore it's only 6 steps.