[1] Yachi received his master's degree at the University of Tokyo Graduate School for Law and Politics in 1969.

He was influenced by Wakaizumi Kei, an international politics thinker who acted as Prime Minister Eisaku Sato's emissary for the negotiation of secret protocols allowing the US to introduce or station nuclear weapons in Japanese territory.

[4] One of Yachi's first tasks as National Security Advisor was to strengthen the new NSC's relations with the American government.

He met with his American counterpart, Susan Rice, as well as cabinet secretaries Chuck Hagel and John Kerry.

[5] On 28 April 2015, he was among the guests invited to the state dinner hosted by U.S. President Barack Obama in Abe’s honor at the White House.