Crown Prince Hyojang (Hanja: 孝章世子; Born: 1719 - Died: 1728) was the eldest son of King Yeongjo, 21st Monarch of Joseon Dynasty. He was installed as Crown Prince at the age of seven in 1725, but died in the young age of nine. I think, this is the posthumous king who died in very young age. What a pity.
After King Yeongjo made the Crown Prince Sado die locked in a wooden rice chest, he adopted his eldest grandson (King Jeongjo), the eldest son of the Crown Prince Sado, to be a foster son of the Crown Prince Hyojang, thereby carrying on the royal line. As King Jeongjo ascended the throne, the Crown Prince Hyojang received a posthumous title of King Jinjong as a foster father of the king and later in 1908, received a posthumous title of the Emperor to be the Emperor So of the Korean Empire (진종소황제/眞宗昭皇帝).
His consort, Queen Hyosun of Poong-yang Cho Clan (孝純皇后, 1715-1751) was installed as Crown Princess in 1727, and conferred the title of Hyeonbin (賢嬪) in 1735. She died at the age of 36 without an heir. When King Jeongjo ascended the throne, she received a posthumous title of Queen Hyosun and in 1908, was again granted with the title of the Empress Hyosun with an epithet ‘So.’
He was buried at the Royal Tomb of Yeongneung (영릉/永陵), a part of Paju Samneung Royal Tomb Cluster (파주삼릉/坡州三陵), located at 89 Samneung Avenue/Samneungno, Bongilcheon-ri san 15-1 beonji, Jori-eup, Paju City Gyeonggi Province. He was posthumously known as King Jinjong Ollyang Yemyeong Cheolmun Hyojang the Great (진종온량예명철문효장대왕/眞宗溫良睿明哲文孝章大王).