In the early half of the 6th century, Baekje and Shilla began their advances into the Gaya realm. In defending themselves from Goguryeo’s southbound activities, they shared a common interest, but when it came to the issue of advancing toward Gaya, they were competitors. Yet they had to refrain from exchanging blatantly hostile actions, as the Goguryeo threat was also getting worse. In the Nihon Shog i’s “Gyeche-gi” record, there are references which could shed some light upon the situation that was unfolding at the time. Previous studies tended to ignore this record or choose to cite it rather arbitrarily, while in this article it is examined carefully to verify how much of this record we could actually rely on. The record seems rather genuine, so hopefully Baekje and Shilla’s advances into the Gaya realm and the Gaya entities’ responses in the early half of the 6th century could be revealed more vividly by properly examining it. In response to Baekje’s advances into the Gaya region, Gara-guk approached Shilla and sought out for a marital arrangement. Shilla was also concerned about Baekje’s making inroads within the Gaya realm, and in order to secure its own foothold in the Gaya region decided to agree to Gaya’s offer. But when Shilla annexed some parts of the Gaya union, Taksun-guk (one of the Gaya entities) vehemently protested. In response, Shilla declared the marriage alliance annulled and threatened Taksun-guk, which unsuccessfully attempted to defuse the situation with Japanese Wae’s intervention. Later, Shilla tried to seize Taksun-guk with Baekje’s help. In the wake of the Shilla-Baekje allied forces’ invasion of Taksun-guk, an inter-regional conference was held at An’ra(-guk), which was located near the hot zone. In order to secure the safety of the Gaya union, An’ra invited Japanese Wae into the equation, and exploited the competitive nature of the Shilla-Baekje relationship. The result was a successful convening of an interregional conference, which led to the invasion indefinitely put on hold.