Standards of Proof in Japan and the United States

Kevin M. Clermont, Cornell Law School


Published in: Cornell International Law Journal, vol. 37, no. 1 (2004). Available online at:

This article treats the striking divergence in standard of proof for civil cases—the required degree of persuasion for the factfinder—between Japanese and U.S. law. The civil-law Japan requires proof to a high probability similar to the criminal standard, while the common-law United States requires only that the burdened party prove the fact to be more likely than not. This divergence not only entails great practical consequences, but also suggests a basic difference in attitudes toward the process of trial.

As to the historical causation of the difference in standards of proof, civil-law and common-law standards diverged in the late eighteenth century, probably because of one system’s French Revolution and the other’s distinctive procedure. The French Revolution, in the course of simplifying the civilian law of proof, hid the standards of proof from view. Meanwhile, the common-law jury served to induce judges to articulate standards of proof for the adversary system.

As to the current motivation to adhere still to the old standards, the different standards conform to the subtle differences between the two systems’ procedural objectives. The civil-law system seeks the legitimating benefits of the myth that its courts act only on true facts and not on mere probabilities. Common-law courts seek legitimacy elsewhere, perhaps in other myths, and thus are free to adopt the standard of proof that more fairly and efficiently captures the real truth of the case.