Samurai mastered sword techniques so thoroughly that their movements became automatic, allowing them to fight effectively even while semi-conscious.

The phenomenon described is known in Japanese martial arts as 'Mushin' or 'mind without mind.' This state occurs when a practitioner's training is so ingrained that they no longer need to consciously process their movements. From a neurological perspective, this involves the basal ganglia and the cerebellum, which handle procedural memory and motor control. Over years of practice, these areas take over complex tasks from the prefrontal cortex, which is responsible for slow, deliberate decision-making.Miyamoto Musashi, perhaps the most famous samurai in history, documented these concepts in his 1645 work 'The Book of Five Rings.' He emphasized that a warrior must make his everyday stance his fighting stance and his fighting stance his everyday stance. This level of dedication leads to 'long-term potentiation,' a process where synaptic connections between neurons are strengthened through frequent activation. This allows for reaction times as fast as 150 to 200 milliseconds, which is near the physical limit of human capability.Modern studies by institutions like the Max Planck Institute have shown that experts in physical disciplines have higher white matter integrity in brain regions associated with their craft. For a samurai, this meant that even if they were exhausted or dazed, their bodies could execute precise strikes and parries. This 'automaticity' is why elite warriors could survive battles that lasted for hours, as their brains were effectively offloading the heavy cognitive load of combat to the more efficient motor systems of the body.