one, in 1601, successfully obtained from the Joseon court the promise of a normalizing of relations upon the return of remaining Joseon captives. As Ming troops continued to be present in Korea following the withdrawal of Japanese forces, the major incentive for Joseon for the normalization of relations with Japan was the withdrawal of the Chinese soldiers from their territory. The Ming Chinese themselves were causing havoc, and their presence continued to strain Joseon's national economy and infrastructure. In response to the Joseon request, Yoshitoshi promptly released several Joseon prisoners and between 1603 and 1604 helped the Joseon envoys to repatriate a further 3,000 by organizing negotiations at Kyoto with Tokugawa Ieyasu, by then the shogun of Japan. In the continuation of the diplomatic talks toward peaceful relations, Joseon in 1606 expanded its conditions and demanded that the shogun write a formal letter requesting peace, and to extradite the Japanese soldiers who had defiled the Joseon Royal Tombs near Hanseong. Realizing that the Shogunate would never agree to such a request, Sō Yoshitoshi sent a forged letter and a group of criminals instead; the great need to expel the Ming soldiers pushed Joseon into accepting and to send an emissary in 1608. The end result was a return of Joseon prisoners and the restoration of diplomatic and trade relations between the two countries. Aftermath and conclusion The Japanese invasions were East Asia's first regional wars involving massed armies equipped with modern weapons. The conflict saw the regular employment of Japanese armies of up to 200,000 men, Ming Chinese armies of 80,000, and the ongoing deployment of local Korean forces numbering in the hundreds of thousands. The invasions also stood as a challenge to the existing Chinese world order on two levels: the military, in which the war challenged Ming China's status as the supreme military power in East Asia, and the political, in which the war affirmed Chinese willingness to aid in the protection of its tributary states. Losses and gains Contrary to Toyotomi Hideyoshi's intentions, the cost of the Japanese invasions of Korea significantly weakened the Toyotomi clan's power in Japan. After Hideyoshi's death, his young son Toyotomi Hideyori became head of the Toyotomi clan. However, the losses suffered by varying daimyōs during the campaign were a contributing factor to the imbalance of power in Japan after the war. As the western-based daimyōs of Kyushu and western Honshu (partially