Because Katakiuchi was a duel, it was allowed for the target of the revenge, or the opponent, to act in self-defense by a counterattack; if the opponent killed the avenging party, this was called 'Kaeriuchi.'
なお、敵討は決闘であるため、敵とされる側にもこれを迎え撃つ正当防衛が認められており、殺害した場合は「返り討ち」と呼ばれる。