When Hyeon Go was describing to Damdeok about how Baekje was divided into East and West Baekje in Episode 13 of Tae Wang Sa Shin Gi before their attack, I couldn’t help but wonder after they showed a map of Bakeje territory. Grabbed a screenshot of the clearest frame I could get.

The map as shown in the screencap shows the map that we knew all along, Baekje bordered by Shilla, Kaya and Goguyreo. What is weird is West Baekje is actually across the sea and occupies parts of East China.

And being the history buff that I am, I went and wiki information on Baekje and got the map below which showed that Baekje only had territory on the Korean penisular. Similar searches for information about West Baekje and maps yielded the same results. Everything was similar but West Baekje was not reflected.

Although controversial, some Chinese and Korean records indicate that Baekje territory included parts of present-day China, across the Yellow Sea. You can read about the history records on this in Wikipedia.

After defeating Goguryeo in 371, Baekje had become a dominant power in East Asia, whose influence was not limited to the Korean peninsula. That state’s King Geunchogo seized several coastal cities of China, notably in Liaoxi and Shandong, to retain its superiority over Goguryeo and a variety of southern Chinese dynasties, which had arisen within the context of extended civil wars caused by the fall of the Han Dynasty in 220 CE and the concomitant invasions of foreign tribes, including but not limited to the Xiongnu and Xianbei (Wu Hu). This was from Gwanggaeto the Great of Goguryeo Wiki.

I also posted the question on forums and this was the answers I got.

Answered by dramaok @ soompi forums

YES you’re right. this is controversial, but as is according to TWSSG, there is indeed West and East Baekje, which are divided by Bohai/Balhae sea. West Baekje (better known as Dae-Ryuk Baekje for Continent Baekje) would be present day Hebei, China (you know, Qingdao beer ^^). because China denies this, and Korean records that directly link to it are destroyed or missing it is very controversial and most ppl only refer to Baekje as just that, the kingdom near present day Seoul and Incheon of South Korea.

However, on closer examinations of both Chinese and Korean records, and Western scholarship, there has been many indirect links to the existence of a West Baekje, which was even greater in geography and population.

For example, Chinese scholar/librarian 宋書 recorded “Baekje is west to Yo-Ha river”.

This is another map which I got from jebusrocks @ China History Forum.

And this map clearly shows that Baekje did indeed split into West and East Baekje at the peak of its powers. So regardless whether they established permanent settlements or a few military outposts since no Baekje artifacts were found from there or not publicised by the Chinese authorities, it is true that Paekche did exert some control over parts of China sometime in the 4th century.

So despite Tae Wang Sa Shin Gi being a pure fantasy television drama, it does have some merit in not twisting history in this area. History is fascinating.