The Japanese had never forgiven the formidable and unprovoked invasion of their country by Kublai Khan. The Japanese are by nature a military nation, and the Chinese writers themselves describe them as "intrepid, inured to fatigue, despising life, and knowing well how to face death; although inferior in number a hundred of them would blush to flee before a thousand foreigners, and if they did they would not dare to return to their country. Sentiments such as these, which are instilled into them from their earliest childhood, render them terrible in battle." Emboldened by their success over the formidable Mongols the Japanese treated the Chinese with contempt, and fitted out piratical expeditions from time to time with the object of preying on the commerce and coasting towns of China. To guard against the descents of these enterprising islanders the Chinese had erected towers of defense along the coast, and had called out a militia which was more or less inefficient. On the main they did not so much as attempt to make a stand against their neighbors, whose war junks exercised undisputed authority on the Eastern Sea. While this strife continued a trade also sprang up between the two peoples, who share in an equal degree the commercial instinct; but as the Chinese government only admitted Japanese goods when brought by the embassador, who was sent every ten years from Japan, this trade could only be carried on by smuggling. A regular system was adopted to secure the greatest success and profit. The Japanese landed their goods on some island off the coast, whence the Chinese removed them at a safe and convenient moment to the mainland. The average value of the cargo of one of the small junks which carried on this trade is said to have been $20,000, so that it may be inferred that the profits were considerable. But the national antipathies would not be repressed by the profitable character of this trade, and the refusal of a Chinese merchant to give a Japanese the goods for which he had paid lit the embers of a war which went on for half a century, and which materially weakened the Ming power. During the last years of Chitsong's long reign of forty-five years this trouble showed signs of getting worse, although the Japanese confined their efforts to irregular and unexpected attacks on places on the coast, and did not attempt to wage a regular war. In the midst of these troubles, and when it was hoped that the exhortation of his ministers would produce some effect, Chitsong died, leaving behind him a will or public proclamation to be issued after his death, and which reads like a long confession of fault. Mea culpa, exclaimed this Eastern ruler at the misfortunes of his people and the calamities of his realm, but he could not propound a remedy for them.