The Cast Keyhole is a puzzle from Hanayama’s Huzzle Cast series, designed by Finland’s Vesa Timonen. It consists of two flat pieces with angled notches and ridges, inspired by the bit of a key, the toothed part that goes into the lock. Fitted into each other, they form a small three-dimensional maze that has to be navigated to separate them.

• BrandHanayama
• DesignerVesa Timonen
• MaterialZinc alloy with metal plating
• SizeApprox. 6.9 × 2.6 × 4.5 cm
• Pieces2
• DifficultyLevel 4 of 6 (Hanayama scale)

Mechanism

Each piece on its own looks very simple: flat surfaces with a few concave and convex notches. The difficulty appears when you combine them, because the notches in one act as walls and passages for the other. The puzzle thus works as a three-dimensional maze: you have to turn and slide the pieces along a specific path, and any move off that path is blocked. Reassembling it requires the same precision as taking it apart.

The finish combines gold and shiny chrome, and it comes in the brand’s usual black box.

What level it suits

Hanayama places it at level 4 on its scale of 1 to 6. It is a good example of the style of Timonen, who also designed other models in the series such as the Hook and the Dial: few pieces, clean shapes and a path to be discovered with patience. It suits those who have already solved an intermediate-level puzzle.