Excavations in the Ghaggar-Hakra basin in Haryana have yielded a collection of terracotta tablets inscribed with the 'Vak-Shuddhi' code, dated to approximately the 5th century BCE. The tablets detail a strict philosophy of linguistic integrity, outlining the moral and metaphysical consequences of untruthful speech.
These artifacts represent some of the earliest physical evidence of the Vedic emphasis on 'Satya' (truth) as a foundational principle of social order. The brevity and precision of the aphorisms suggest they were used as instructional tools for early philosophical students in the Kuru-Panchala region.