Iaido is a Japanese martial art associated with the smooth, controlled movements of drawing the sword from its scabbard, striking or cutting an opponent, removing blood from the blade, and then replacing the sword in the scabbard.
These four elements are the building blocks of Iaido.
While new students of iaido may begin learning with a wooden sword (bokken) depending on the teaching style of a particular instructor, many of those who study Iaido use an unsharpened sword (Iaito). Advanced practitioners of Iaido, use a sharpened metal sword (shinken).
Iaido teaches the use of actual metal weaponry, it is almost entirely based on the teaching of forms, or kata. Multiple person kata do exist within some forms of iaido, but the iaidoka (practitioners of iaido) will usually use bokken for such kata practice. Iaido does not include direct competition or sparring of any kind.
Because of this non-competitive aspect, and Iaido's emphasis on precise, controlled, fluid motion, it is sometimes referred to as moving Zen or "gyuzen", with emphasis placed on movement, balance and breathing.
The term Iai is taken from the phrase 'Tsune ni itte, kyu ni awasu' - the meaning of which is "whatever we may be doing or wherever we may be, we must always be prepared for any eventuality".
Haruna Matsuo Nanadan Kyoshi December 1994