If you are familiar with Japanese martial arts, particularly Kendo, you may have heard the term ai-uchi. Sasama Yoshihiko, in Zusetsu Nihon Budo Jiten, defines the term as meaning when two or more people attack a single enemy at once, such as the "swarming" used by police to subdue an unruly prisoner. Japanese history documents instances of sannin-ai-uchi (three against one) attacks against a single samurai. The common meaning of ai-uchi is when two opponents both strike and connect at the same time.
In combat, there are three possible outcomes:
- You win and the opponent dies
- Opponent wins and you die
- Both of you kill each other (ai-uchi )
Two out of three chances of killing the enemy is not bad for a battlefield commander, but two out of three chances of dying is certainly bad for the individual soldier. The classical warrior was pretty much resigned to the fact that the odds were two to one that he would die in battle. It was always possible during a mutual strike that one or both of the attackers could live. If you strike with greater force or more accurately than your opponent, you may live and the opponent may die. This may be likened to engaging the enemy because you think you may be able to hurt him more than he may hurt you.
In free-sparring, ai-uchi commonly occurs when two opponents strike each other at the same time so that their points cancel each other. It also means being willing to give up a point so you may earn more points, such as taking a one-point kick to the abdomen while delivering two-point kick to the opponent's head.
Mutual strikes also occur when two attacks collide, such as when two punches meet head-on. If both punches were delivered correctly, their collision force will not be at its maximum since the power of both punches being focused at the targets, not at the point where the fists collide. If one punch has more speed and power than the other, the fist may not be harmed, while the other fist may be injured.
When free-sparring, you should be aware of ai-uchi and use it to your advantage.