The seated gilt-bronze Vairocana Buddha and the seated gilt-bronze Amitabha Buddha of Bulguksa Temple are a unique combination as a pair. They both have peculiar mudras using opposite sides of their hands in contrast to the conventional hand gesture: holding the right index finger instead of the left for the Vairocana Buddha or raising the left hand instead of the right for the Amitabha Buddha. This not only differentiates them from other contemporaneous Buddhist statues but also represents the uniqueness of Buddhist art history in Korea. However, there have not been many studies about them, and their production date is a point of argument among researchers. This article obtains two objectives. After first reviewing their production dates, I examined them based on why the Vairocana Buddha statue and the Amitabha Buddha were paired up and why this peculiar iconography emerged, based on the religious thoughts. I conclude that their production period is from the mid- to late 9th century. This is not only because they are similar in style—physical proportion similar to an elongated isosceles triangle, volumes of the face, exaggerated features on face, and the reversed hand gesture—to the Buddhist statues from the 9th century but also because the peculiarity of being a Vairocana Buddha, which is connected to the royals and enshrined in their capital (Gyeongju), cannot coexist with the Hwaeom thought of the Uisang lineage. As widely known, Buddhism in the Unified Silla period shifted from Beopsang (Ch. Faxiang, Sk. Yogācāra) School to Hwaeom (Ch.