The Himitsu-Bako is an enclosed box, seemingly with no opening and you cannot even tell which side is the top or bottom.
Its mechanism is quite tricky. It is impossible to open it unless you follow the exact step-by-step procedure, such as pushing or pulling a certain side at a time, designed specially for it.
To be opened, each box must be rotated, turned and moved in a specific way.
It takes between 1 to 1536 moves (STEP) to open a box.
The size of a Japanese puz