Ki Ch'à Âl (; died June 16, 1356), also known by his Mongolian name Bayan Buka, was a political figure and nobleman in the late Goryeo dynasty. After his younger sister, Empress Gi who was the wife of Toghon Temür giving birth to a prince, Ki Ch'à Âl was then honoured as Internal Prince Deokseong.
Ki received a government post from the Yuan dynasty and appointed as the Grand Minister of Education or da situ () in 1340. In 1353, Ki was appointed as a manager of the Liaoyang Branch Secretariat. Since the Haengju Ki clan was regarded as a powerful family in Goryeo, he was given preferential treatment with or equal to that of the Goryeo ruler during his stay in Yuan. On June 16, 1356, Ki was invited to a palace banquet by King Gongmin himself, but as soon as he entered it, the king accused him and Kwà Ân Kyà Âm, both members of the pro-Yuan faction, of plotting treason and conspiracy, and they were arrested and executed them on the spot. Ki Yu-gà Âl and ÃÂljei Buka were also killed by the king's orders. This event is present-day known as "Byeongsin coup" in Korean history.