The Stanford Encyclopedia of Philosophy's own entry on Mohism states plainly that little is known of Mozi's life, not even which state he was from; only a rough floruit of circa 430 BCE, contemporaneous with Socrates, can be given with any confidence.
What would resolve this Further archaeological or textual discovery bearing on Mozi's home state and exact birth and death years; the surviving record only supports a floruit of roughly 430 BCE.
OpenEarly Chinese intellectual history, classical Chinese textual studiesStanford Encyclopedia of Philosophy