A different side of Jang Ok Jung but the main character is of course, Dong Yi a palace maiden who has stolen the king's love.
This drama is mainly focused on Choi Suk Bin, but it potrays Jang Ok Jung too, but as the villain here
Both dramas tell the story of King Sukjong and his wives from totally different sides/perspectives. Royal Consort Choi's side is told on Dong Yi while Royal Consort Jang's side is told in Jang Ok Jung.
I feel that in both dramas the kings have the same nature. Also, in Jang Ok Jung the king falls for a palace maid whereas in Moon embracing the sun, the king falls for a shaman (both of a low class). Both love stories begin during childhood.
They are both about a romance between the king, and a lowly peasant who later becomes one of his concubines. There is also hate towards the main lead girl due to her low social status, and if you have seen Dong Yi, Yi San is King Sukjon's (the king in Dong Yi) which is also the king in Jang Ok Jung, is his great-grandson.
In both Jang Ok Jung and The Throne, we see Yoo Ah In playing a Joseon Royal. King Sukjong (Yoo Ah In's character in Jang Ok Jung) is also one of the main characters in Jang Ok Jung. This means that Jang Ok Jung is a show that might be enjoyed by The Throne fans since it has both Yoo Ah In plus the audience get to know more about King Sukjong (who is only barely mentioned in The Throne). One must keep in mind that Jang Ok Jung has a little twist in that it tends to be more sympathethis towards Sukjong's concubine Jang Ok Jung, who is more historically known as the more villainous concubine. Jang Ok Jung is the mother of the brother of Prince Sado's father, King Yeongjo.