Despite the Mongol military success , the control of the borderlands remained contested . Pagan did not relinquish its claim to the frontier regions , and the Burmese , apparently taking advantage of Mongol preoccupations elsewhere , rebuilt their forts at Kaungsin and Ngasaunggyan later in 1278 , posting permanent garrisons commanded by Einda Pyissi . But their control was short @-@ lived . The Great Khan 's attention turned to Southeast Asia once more in 1281 . He had had mixed success : his vaunted forces had finished off the last of the Song in 1279 but had again failed to take Japan in 1281 . That year , the Mongol emperor sent another mission to Pagan , demanding tribute yet again . The Burmese king was to send his ten senior ministers accompanied by one thousand cavalry officers to the emperor 's court . ( With Champa , the emperor summoned the king of Champa himself to Beijing . )