Samurai practiced candle-flame meditation to master their fear and maintain focus during battle.

The practice of candle-gazing, known in Japanese traditions as a form of Zazen or in Yogic traditions as Trataka, involves fixed-point concentration to achieve mental stillness. Historically, samurai of the Kamakura period (1185–1333) adopted Zen Buddhism to cultivate 'mushin' or 'mind without mind'. This state allowed them to act instinctively without the interference of fear or ego during high-stakes combat. Modern neuroscience explains this through the regulation of the amygdala, the brain's emotional processing center. By maintaining a steady gaze and controlled breathing, practitioners can lower their heart rate and cortisol levels. A 2013 study published in the 'Journal of Cognitive Enhancement' suggests that focused-attention meditation strengthens the prefrontal cortex. This area of the brain provides top-down regulation over the amygdala, effectively dampening the 'fight or flight' response. Furthermore, the specific act of staring at a flame engages the parasympathetic nervous system. This physiological shift promotes a state of 'relaxed alertness', which was vital for warriors who needed to be both calm and ready for explosive action. Researchers at institutions like the Max Planck Institute have found that such mindfulness practices can physically increase gray matter density in regions associated with emotional regulation. For the samurai, this mental conditioning was just as important as their physical training with the katana.