Abstract
This paper reviews the Supreme Court of Japan in Decision of December 12, 2017, 2016 (Kyo) 43 (2011) concerning arbitrator's duty of disclosure and reasonable investigation under the Japan Arbitration Act (Arbitration Act). The Supreme Court of Japan recently issued a precedential decision interpreting, for the first time, the arbitrator disclosure requirements of the Arbitration Act. Under Article 18(4) of the Arbitration Act, arbitrators have an ongoing obligation to disclose circumstances which may give rise to justifiable doubts as to their impartiality or independence. The Supreme Court held that Article 18(4) of the Arbitration Act - requiring arbitrators to disclose all "facts likely to give rise to doubts as to his/her impartiality or independence" - (1) is not satisfied by blanket disclosures or advance waivers of potential future conflicts, and (2) requires disclosure of facts both known to an arbitrator or "that can be normally ascertained by an investigation that is reasonably possible${\cdots}$" This new standard presents opportunities and challenges for enforcing arbitration awards in Japan, and suggests measures that both arbitrators and parties can use to protect their awards. Also, the Supreme Court's new standards for evaluating arbitrator conflict disclosures suggest some measures that both arbitrators and parties to arbitration in Japan can take to protect the enforceability of their awards. The key factual question posed by the Supreme Court's ruling was whether an arbitrator's conflicts check was reasonable. Maintaining records regarding a review of potential conflicts or any investigation provides a ready source of proof in case of a future challenge. The Supreme Court has spoken clearly that so-called advance waivers of potential conflicts are not effective under Japanese law. Instead, to the extent that potential conflicts arise during the course of arbitration, they should be specifically disclosed.