Why is Myeongjeongjeon, the main hall of Changgyeonggung, facing east?

• Main halls and other important pavilions in the five major royal palaces of the Joseon Dynasty are all facing south, their main direction. However, there is one building that faces east within the palaces: Myeongjeongjeon, the main hall of Changgyeonggung Palace. 
• Changgyeonggung Palace burned down during the Imjin War, the Japanese Invasions of Korea (1592-1598), and its reconstruction was decided upon in the seventh year of Gwanghaegun, when Kim Il-son submitted an appeal to argue that Myeongjeongjeon should face south, encouraging heated discussions about its main direction. According to the records of that time, many argued that the palace’s main hall should face south, but the original direction of east was pursued through rounds of appeals and discussions. Those who argued for the original direction said they could not make a rash revision to the venerable system on the basis that their insightful ancestors had decided that Myeongjeongjeon face east and that the direction of south was inauspicious for Myeongjeongjeon according to the principle of pungsu (feng shui). 
• Given the fact that the Joseon Dynasty followed the principle of pungsu when it moved its capital to Hanyang or placed important buildings on the sites of its palaces, it is assumed that the main hall of Changgyeonggung Palace was also placed facing east in accordance with geomancy principles.