Kenjutsu is a word used for the discipline of the Japanese sword for warriors. It, in it’s most fundamental forms, is designed to be as effective as can be for Samurai to win duels and battles. Grappling, binding, and combination-use with tanto (knives) are commonplace in Kenjutsu schools. There are schools that teach Kenjutsu for armored (yoroi) and unarmored use of the sword.
Kendo is an evolution of Kenjutsu designed for sport. The word means “sword way” or “way of the sword”. Competitors typically don protective armor (bogu) and use bamboo swords called shinai. The sport of Kendo is very important to Japanese culture to which most high schools and colleges have their own clubs and teams. Unlike Kenjutsu, Kendo has strict rules against grappling and targeting certain parts of the body.
Iaido is a sword art that is derived from Kenjutsu but focuses on one’s mindset rather than ability to spar. Practitioners drill in forms that focus on drawing, cutting, de-blooding, and returning a katana to its sheath (saya). Focus is placed on preparedness of mind when facing off with a theoretical opponent. Metal training blades (iaito) and sharp cutting blades (shinken) are typically used in Iaido. Tameshigiri (cutting of targets) is also practices in Iaido.