What is the primary characteristic of the Paek Chee kingdom?

The primary characteristic of the Paek Chee kingdom, also known as Baekje, is indeed its focus on military strength. Throughout its history, this kingdom was known for its significant military capabilities which played a crucial role in both its expansion and defense. The strategic development of a strong military allowed Paek Chee to exert influence over neighboring territories and to engage effectively in both warfare and diplomacy, which were essential for maintaining its power during the Three Kingdoms period of Korea.

While the other options—advancements in technology, development of the arts, and trade expansion—were also present during the kingdom's era, they were generally considered secondary to its military conquests. The military strength provided a foundation for the expansion of the kingdom's trade and cultural practices, but the kingdom’s identity was predominantly shaped by its martial prowess and the defense of its territory against rivals like Silla and Goguryeo.