Why did Kaidu oppose Kublai Khan’s rule?

Kaidu’s opposition to Kublai Khan was primarily rooted in a dispute over the legitimacy of the Mongol empire throne and a fundamental ideological divide regarding the future of Mongol culture.12

As a grandson of Ögödei—who had been personally designated by Genghis Khan as his successor—Kaidu viewed himself as the representative of the rightful line of succession. He resented that the throne had shifted from the line of Ögödei to the line of Tolui in 1251.12

Furthermore, the conflict reflected a deep cultural split. Kaidu led those who opposed Kublai’s abandonment of traditional steppe customs in favor of an "alien," China-centered culture. By identifying himself with the Chinese world and adopting Confucian administrative practices, Kublai alienated the steppe aristocracy, who viewed his governance as a departure from their nomadic heritage. This tension fueled over 30 years of warfare, during which Kaidu maintained control over Turkistan and parts of Mongolia until his death in 1301.21