Fudo Myo-o, one of the protective deities in Buddhism, is often shown wielding a rope and a sword. It is with his sword that he cuts through the illusions to reveal the unadulterated reality. The rope simultaneously is used to keep him affixed in the swirling currents of change.
Fudo (without movement) at its core symbolizes the attitude of endurance. Shin, the Chinese pronunciation, or kororo in Japanese, is the mind, and refers to the heart or spirit of the person. A practitioner of budo aims to achieve Fudo shin, a frame of mind that is immovable or unshaken by the opponent or the multitude of changes that life is sure to impart. It is a developed mindset that is unperturbed, yet flexible, not stuck as Soho Takuan might have said, and is able to respond to a myriad of situations . In the realm of modern budo, though its origins lie in kenjutsu and iaijustsu, we now train to perfect ourselves, our techniques, and our character such that we remain steadfast and serve as a beacon for others, like a lighthouse guiding others along the way.
With regards to kendo and iaido, fudoshin has a strong relation to shugyo (austere training). The unwavering mindset allows us to continue to practice through injuries, bone-chilling winters, and blistering summers. It is in this continuation and perseverance that the character is slowly refined and the true strength revealed, polished by the flow of time.
Suzuki Sazo sensei kyoshi 7dan （鈴木佐三 教士七段)