Kenka ryōseibai (喧嘩両成敗) means that both parties to a quarrel are punished. Article 8 of the Imagawa kana mokuroku, the law code of the Imagawa family of 1526, states: Kenka ni oyobu yakara, rihi o ronzezu, ryōhō tomo ni shizai ni okonau beki nari. Those who come to blows shall both be put to death, without regard to who was right.
A publication of the Shizuoka Prefectural Library notes that this was the first appearance of the rule in the law of a domain.