Emperor Wen of Han
When Emperor Wen of Han was on the throne, Liu Pi's son Liu Xian and Crown Prince Qi (later Emperor Jing of Han) were involved in a game of "Liubo" which ended in the crown prince accidentally killing Liu Pi's son with the chess board. Out of revenge and reflecting his growing distrust of the Emperor, Liu Pi started building up his wealth and military power within his territory. Emperor Wen believed his son was at fault for Liu Xian's death and did not hold Liu Pi accountable for his aggressive actions.