The Cast Helix is a puzzle from Hanayama’s Huzzle Cast series, designed by Japan’s Akio Yamamoto. It is inspired by the bellflower or morning glory: two five-pointed flower-shaped pieces, joined by a rivet, and a silver helix-shaped ring that passes through them. The aim is to remove the helix and put it back.

• BrandHanayama
• DesignerAkio Yamamoto
• MaterialCast metal
• SizeApprox. 5 × 5 cm
• PiecesTwo riveted flowers and a helical ring
• DifficultyLevel 5 of 6 (Hanayama scale)

Mechanism

The two flowers rotate on the rivet that joins them. Each has a spiral groove cut into it, and the two grooves always cross at right angles, forming a square opening through which the ring passes. As you turn the flowers and rotate the helix, the whole piece changes shape, so it is fun to handle even before you start looking for the solution.

The original concept dates back to 1990, and several details were added for this version that make the challenge harder. The intended image is that of an opening bud, with tendrils curling around it.

What level it suits

Hanayama grades it at level 5 on its scale of 1 to 6, the band it reserves for experienced solvers. It is recommended for those who have already solved several level 3 and 4 models and do not mind spending several sessions on it.