Romance of the Three Kingdoms X, also known as Sangokushi X (三國志X) in Japan, is the 10th installment in the Romance of the Three Kingdoms (Sangokushi) strategy game series by Koei. It was originally released in the summer of 2004 and the PUK expansion was released several months afterwards. Sangokushi X abandoned many of Sangokushi IX's concepts and favors elements from Sangokushi VII and Sangokushi VIII, as well as Taikou Risshiden, which are in RPG format.