In karate, to perform a difficult feat such as breaking a brick by a sharp blow with the edge of the hand, the mind must first be briefly made completely blank. The blow is then spontaneous, immediate, delivered by force, and unhindered by calculating thought. Opponents do not look into each other's eyes. Why? Because if the intention to make the next move arises, the thought will reveal itself by the slightest loss of balance when thought tends to affect the body's muscles. The opponent divines the intention by gazing into the eyes, so they look down to the chest.
-- Notebooks Category 15: The Orient > Chapter 3: China, Japan, Tibet > # 168