The old success of the Mongols did not desert them on land, and Kublai received some consolation for his rude repulse by the Japanese in the triumph of his arms in Burmah. The momentary submission of the King of Burmah, or Mien, as it was, and is still, called by the Chinese, had been followed by a fit of truculence and open hostility. This monarch had crossed over into Indian territory, and had assumed the title of King of Bengala in addition to his own. Emboldened by his success, he did not conceal his hostility to the Mongols, sent a defiant reply to all their representations, and even assumed the offensive with his frontier garrisons. He then declared open war. The Mongol general, Nasiuddin, collected all the forces he could, and when the Burmese ruler crossed the frontier at the head of an immense host of horse, foot, and elephants, he found the Mongol army drawn up on the plain of Yungchang. The Mongols numbered only 12,000 select troops, whereas the Burmese exceeded 80,000 men with a corps of elephants, estimated between 800 and 2,000, and an artillery force of sixteen guns. Notwithstanding this numerical disadvantage the Mongols were in no way dismayed by their opponents' manifest superiority; but seldom has the struggle between disciplined and brute force proved closer or more keenly contested. At first the charge of the Burmese cavalry, aided by the elephants and artillery, carried all before it. But Nasiuddin had provided for this contingency. He had dismounted all his cavalry, and had ordered them to fire their arrows exclusively against the elephant corps; and as the Mongols were then not only the best archers in the world, but used the strongest bows, the destruction they wrought was considerable, and soon threw the elephants into hopeless confusion. The crowd of elephants turned tail before this discharge of arrows, as did the elephants of Pyrrhus, and threw the whole Burmese army into confusion. The Mongols then mounting their horses, charged and completed the discomfiture of the Burmese, who were driven from the field with heavy loss and tarnished reputation. On this occasion the Mongols did not pursue the Burmese very far, and the King of Burmah lost little or no part of his dominions, but Nasiuddin reported to Pekin that it would be an easy matter to add the kingdom of Mien to the Mongol empire. Kublai did not act on this advice until six years later, when he sent his kinsman Singtur with a large force to subdue Burmah. The king took shelter in Pegu, leaving his capital Amien at the mercy of the conqueror. The Mongol conquests were thus brought down to the very border of Assam. In Tonquin and Annam the arms of Kublai were not so successful. Kublai's son Togan made an abortive campaign in these regions. Whenever an open force had to be overcome, the Mongol army was successful, but when the Mongols encountered the difficulties of a damp and inclement climate, of the absence of roads, and other disadvantages, they were disheartened, and suffered heavily in men and morale. With the loss of his two generals, and the main portion of his army, Togan was lucky in himself escaping to China. Kublai wished to make another effort to subdue these inhospitable regions and their savage inhabitants, but Chinese public opinion proved too strong, and he had to yield to the representations of his ministers.
Kublai was the more compelled to sacrifice his feelings on this point, because there were not wanting indications that if he did not do so he would find a Chinese rebellion on his hands. Notwithstanding his many successes, and his evident desire to stand well with his Chinese subjects, it was already clear that they bore their new leader little love. Several of the principal provinces were in a state of veiled rebellion, showing that the first opportunity would be taken to shake off the Mongol yoke, and that Kublai's authority really rested on a quicksand. The predictions of a fanatic were sufficient to shake the emperor on his throne, and such was Kublai's apprehension that he banished all the remaining Sung prisoners to Mongolia, and executed their last faithful minister, who went to the scaffold with a smile on his face, exclaiming, "I am content; my wishes are about to be realized." It must not be supposed from this that Kublai's authority had vanished or become effete. It was absolutely supreme over all declared enemies, but below the surface was seething an amount of popular hostility and discontent ominous to the longevity of the Mongol dynasty. The restless ambition of Kublai would not be satisfied with anything short of recognition, in some form or other, of his power by his neighbors, and he consequently sent envoys to ail the kingdoms of Southern Asia to obtain, by lavish presents or persuasive language, that recognition of his authority on which he had set his heart. In most cases he was gratified, for there was not a power in Eastern Asia to compare with that of the Mongol prince seated on the Dragon Throne of China, and all were flattered to be brought into connection with it on any terms.