Why is a spey blade called a spey blade?

A spey blade is called a spey blade because it is designed for a specific type of fishing known as spey fishing, which originated in the Spey River in Scotland. This type of blade features a unique shape with a pointed tip and a curved edge, allowing for efficient casting and fishing techniques used in river environments. The design facilitates the rolling cast technique that is characteristic of spey fishing, making it easier to present flies to fish in a controlled manner.