The Knifehand Mountain Block (also called Single Knifehand Mountain Block, or sonnal waesanteul makgi) is a Mountain Block with both hands held in a knifehand position.
The palm of the raised hand faces the head. The palm of the low hand facing the leg. The fingertips of the raised hand are aligned with the top of the head and the arm is bent at a 90° angle.
The Single Knifehand Mountain Block appears, for example, in the form Cheonkwon.