Datuk Perpatih nan Sabatang is the second of the paired legislator-ancestors, son of the sage Cati Bilang Pandai by Puti Indo Jalito and thus maternal half-brother to Datuk Ketumanggungan. He founds the Bodi Caniago lareh, the egalitarian system in which every lineage head sits as an equal and authority is built upward through deliberation and consensus, captured in the proverb that just as water is shaped round by the bamboo conduit, speech is made round by agreement. Against his brother's hierarchy he sets the principle of level assembly, and the enduring counterpoint of the two men, sometimes framed as debate, sometimes as the peaceable partition of the realm, furnishes the Minangkabau their charter of dual custom. He is also remembered in the related Malay lore of Negeri Sembilan as a founder of its adat perpatih.