Kendo students face each other in standing position to determine victory or defeat wearing protective equipment (bogu) and holding a bamboo sword (shinai). IAIDO is the art of cutting, thrusting and defending with the real sword (Katana) with great diversity of applications against an imaginary opponent.
While sitting, standing, or walking, and being attacked from all sides, the swordsman must anticipate, defend and retaliate. IAI is concerned with attack and defence in terms of ma-ai (distance), hasuji (the center of the sword stroke) and te-no-uchi (grasping the tsuka, the hilt of the sword). In unity with the same is the spirit of entering into the opponent's attack with harmonious sword and body action, to defeat the enemy through his psychological weakness. This is true self-defense.
Nakayama Hakudo, a very important iaido promoter of our era, regarded Kendo and IAIDO as inseparable, comparing them to the wings of a bird. To master the art of the sword, he was convinced that if one of the two was missing perfection could not be obtained.
Yet greater than technique is spiritual training. IAI does not necessarily mean top cut an enemy, but rather to cut the enemy within yourself. Victory in IAI is the non-revengeful heart and the cessation or conflict through not drawing the sword. Thus, you may understand why the IAI of old was called saya-no-uchi, invincibility without drawing the sword.
In other words, IAI is a training process toward human perfection, never of murderous intent, but peaceful-minded. The modern significance of IAI is peace and tranquility for human life. In the largest sense IAI means the Way of Dwelling in Harmony: through endless practice seeking harmony with the Universe.