For centuries, the martial arts have been practiced as both a method of self-defense and a meditative exercise to strengthen one’s harmony of mind and body. One noticeable aspect of martial arts that is often imitated and parodied ad nauseum in pop culture is the kiai. “Kiai” is a Japanese term referring to vocalizations made during or after the execution of an attack in martial arts; the “Hiyah!” often heard in cheesy fighting films. The word is comprised of the characters 気 (energy, spirit) and 合 (harmonize, blend); although it is a Japanese compound, the technique itself is used in martial arts from all over the world. “Ki” (気, also known as “chi” or “qi” elsewhere) is an important concept in Asian spirituality; it is considered a special life force that comes from within one’s soul, and reflects one’s inner spirit (Nagatomo 176). Kiai is commonly explained to the martial arts student as a projection of one’s warrior spirit onto the opponent as a tool of spiritual combat. It is understood by martial artists to be primarily a metaphysical concept integral to the practice of martial arts. In short, kiai is the harmony of one’s ki energy within the self and with the opponent, executed with the aim of perfecting the timing and strength of the attack.
The specific sound of these guttural syllables vary among schools and individuals, reflecting the practitioner’s own expression of their ki. Some schools distinguish between “kakegoe,” simple shouts from the throat made with an attack, and kiai, a projection of ki energy with diaphragmatic breathing. The frequency of use of kiai varies among disciplines; it is used sparingly every 5 or so strikes in Okinawan and Japanese martial arts, much more extensively in taekwondo and is required for every cut made in kendo, Japanese fencing. Martial artist Wendell Wilson warns students that “‘the yell’ is not a trivial, expendable, slightly silly bit of melodrama; rather, it is a core concept and an essential skill to be taken very seriously and to be practiced and refined at every opportunity.” (Wilson 1)
The proper execution of kiai also serves as a physical enhancement of the attack. By expelling the air in the lungs with the diaphragm, the practitioner tenses up their abdominal muscles to guard against a counterattack and prevent the wind being knocked out of them (Villari 56). Additionally, kiai serves to intimidate an opponent, allowing the attacker to follow up and press their advantage. This intimidation connects to the spiritual concept of the use of ki; by projecting strong ki at an opponent with weaker ki, the practitioner wins the spiritual component of the physical battle.
In additional to these physical and psychological effects, the use of kiai serves as a release of aggressive energy that accumulates during intense activities. A study by researchers in England confirmed that Kung Fu practitioners experience aggressive feelings before and during sparring matches. Some utilize martial arts as an explicit way of dealing with aggression in a healthy, controlled way (Fletcher & Milton). Famous kendo master Junzō Sasamori elaborates that kiai “expresses a natural need to exert the strength he [the user] has in his body.” (Sasamori 141)
My research will examine instructional literature and scientific and psychological studies of martial arts to examine the use of kiai as a method of harmonizing the mind and body, executing an attack with the whole of the practitioner’s being. Martial arts pedagogical works, such as Wilson’s essay and Villari’s book, often focus on the spiritual and philosophical purposes of kiai, while scientific studies examine the physical mechanisms and impacts of martial arts practice. A synthesis of both types of sources is necessary confirm the role of kiai in uniting the martial artist’s metaphysical and physical energy in the execution of a proper attack.