七重の鞘に納められ、賽子を貫くほど繊細でありながら水に浮くほど精巧な針を作り上げ、貧しくも工夫に富む鍛冶屋が親方鍛冶屋の娘を妻に迎える本生話。

A birth-story about a poor but ingenious smith who wins the hand of the master smith’s daughter by crafting an exquisite needle, nested within seven sheaths, delicate enough to pierce dice yet float on water.