The Cast H&H is a cast-metal puzzle from Hanayama’s Huzzle Cast series, created by Dutch inventor Oskar van Deventer. It is made up of two pieces shaped like the letter H, interlocked in a way that makes them seem impossible to separate. The challenge is to release them and then join them again in their original position.

• BrandHanayama
• SeriesHuzzle Cast
• DesignerOskar van Deventer
• MaterialCast metal
• Pieces2
• DifficultyLevel 5 of 6 (Hanayama scale)

Design

At first glance the two Hs look identical, but they are not quite: there are small differences between them, and spotting those details is part of the challenge. It is a disentanglement puzzle: it has no catches, springs or hidden parts, just two shapes wrapped around each other. The metal feels pleasant to the touch and the compact assembly fits in the palm of your hand.

Oskar van Deventer is one of the most prolific designers of mechanical puzzles and has created a long list of models for Hanayama, such as the Chain and the Möbius.

What level it suits

Hanayama grades it at level 5 on its scale of 1 to 6, the band intended for experienced solvers. It is not usually solved in one sitting, and it is best tackled after completing several intermediate-level models.