Maritime archaeologist Kenzo Hayashida led the investigation that discovered the wreckage of the second invasion fleet off the western coast of Takashima District, Shiga. His team's findings strongly indicate that Kublai rushed to invade Japan and attempted to construct his enormous fleet in one year, a task that should have taken up to five years. This forced the Chinese to use any available ships, including river boats. Most importantly, the Chinese, under Kublai's control, built many ships quickly in order to contribute to the fleets in both of the invasions. Hayashida theorizes that, had Kublai used standard, well-constructed ocean-going ships with curved keels to prevent capsizing, his navy might have survived the journey to and from Japan and might have conquered it as intended. In October 2011, a wreck, possibly one of Kublai's invasion craft, was found off the coast of Nagasaki. David Nicolle wrote in The Mongol Warlords, "Huge losses had also been suffered in terms of casualties and sheer expense, while the myth of Mongol invincibility had been shattered throughout eastern Asia." He also wrote that Kublai was determined to mount a third invasion, despite the horrendous cost to the economy and to his and Mongol prestige of the first two defeats, and only his death and the unanimous agreement of his advisers not to invade prevented a third attempt.
Under Kublai, direct contact between East Asia and Europe was established, made possible by Mongol control of the central Asian trade routes and facilitated by the presence of efficient postal services. In the beginning of the 13th century, Europeans and Central Asians – merchants, travelers, and missionaries of different orders – made their way to China. The presence of Mongol power allowed large numbers of Chinese, intent on warfare or trade, to travel to other parts of the Mongol Empire, all the way to Russia, Persia, and Mesopotamia.