Duke Gangyang or Prince Gangyang (Korean: 강양공; Hanja: 江陽公; died 1308[a]), born Wang Cha, was a Goryeo royal prince as the first and oldest son of King Chungnyeol and Princess Jeongsin,[1] also great-grandfather of its last monarch, King Gongyang.
As the oldest son and since his mother was King Chungnyeol's first wife, Wang Cha was the one who should become the crown prince.
Yet, due to Yuan dynasty influence on Goryeo after the king's marriage with Kublai Khan's daughter–Qutugh Kelmysh, Wang Cha must give up the crown prince position to his half younger brother.
[2] In 1279 (5th years reign of his father), Wang Cha had to go to the Dongsim Temple (동심사) in Aju, Chungcheong-do (now Asan, South Chungcheong Province) to avoid conflict with the crown prince.
[3] Four years later in 1283, Wang Cha was able to back to Gaegyeong and received his royal title–Duke Gangyang (강양공; 江陽公).