The Old Law represented an archaic legal framework among the Hutt, stipulating that clan chieftains could engage in formal duels given adequate grounds for dispute. This law sanctioned single combat to the death.
Following the obliteration of the Hutt's original planet, Varl, Hutt society underwent a fundamental shift. A legal prohibition, enforced by severe penalties (ranging from banishment and financial ruin to death), was enacted against any Hutt taking the life of another. Consequently, Hutt society transitioned from a focus on military power to economic control, with the preferred method of dealing with rivals becoming financial devastation rather than physical elimination.
The "Old Law" stands as the only known exception to this prohibition. It permits the acknowledged head of a Hutt kajidic to challenge the established leader of another kajidic to a private, deadly duel, provided the challenged party has sufficiently provoked the challenger. The duel's winner would be considered to have justice on their side and would not face prosecution for killing another Hutt.
Despite its legality and acceptance, most Hutts viewed challenges under the Old Law unfavorably, as it led to the demise of a valuable leader, a loss considered wasteful. Jabba's grand-uncle, Jiliac, met his end at the hands of Durga in such a duel at his Winter Palace, as retribution for Jiliac's poisoning of Durga's father, Aruk the Hutt.