The bakufu set a legal precedent that if the real husband killed his wife first for the reason of adultery, the adulterer who had brought about the cause would be considered as megataki (adulterer), and for this reason, even if the husband practiced megataki uchi (revenge oneself on the adulterer), it would not constitute a crime of murder, and thus, the husband was innocent.
姦夫を妻敵討として殺害した本夫が姦夫の親族から殺人罪で告発された裁判で、本夫が姦通を理由に先に妻を殺害してしまえばその原因を作った姦夫は妻敵になるのであるから、本夫が妻敵討を行っても殺人罪とはならず無罪となるという判例を下した。