In practical use this often refers to the scream or shout made during an attack, used for proper breathing as well as debilitating or distracting the enemy. There are two underlying strategic methodologies to the application of force in Japanese martial arts. One is the , and the other is the . Implicit in these concepts is their separate but equal and interrelated nature, in keeping with their philosophical relationship to the Chinese principles of yin and yang (Jap.: "in" and "yō"). The hard method is characterized by the direct application of counter-force to an opposing force. In practice, this may be a direct attack, consisting of movement directly towards the opponent, coinciding with a strike towards the opponent. A defensive technique where the defender stands their ground to block or parry (directly opposing the attack by stopping it or knocking it aside) would be an example of a hard method of defense. Hard method techniques are generally conceptualized as being linear. The soft method is characterized by the indirect application of force, which either avoids or redirects the opposing force. For example, receiving an attack by slipping past it, followed by adding force to the attacker's limb for the purpose of unbalancing an attacker is an example of soft method. Soft method techniques are generally conceptualized as being circular. These definitions give rise to the often illusory distinction between "hard-style" and "soft-style" martial arts. In truth, most styles technically practice both, regardless of their internal nomenclature. Analyzing the difference in accordance with yin and yang principles, philosophers would assert that the absence of either one would render the practitioner's skills unbalanced or deficient, as yin and yang alone are each only half of a whole. Openings, initiative, and timing are deeply interrelated concepts applicable to self-defense and competitive combat. They each denote different considerations relevant to successfully initiating or countering an attack. In Japanese martial arts, is "the decisive moment when a killing action is initiated." There are two types of initiative in Japanese martial arts, , and . Each type of initiative complements the other, and has different advantages and weaknesses. Early initiative is the taking advantage of an opening in an opponent's guard or concentration ("see "suki", supra"). To fully take the early initiative, the attack launched must be with total commitment and lacking in any hesitation, and virtually ignoring the possibility of a counter-attack by the opponent. Late initiative involves an active attempt to induce an attack by the opponent that will create a weakness in the opponent's defenses, often by faking an opening that is too enticing for the opponent to pass up.