The biggest reason is to solve the problem of the legitimacy of the Toyotomi regime

He comes from a humble background, and his ancestors are not from the Genpei family samurai. According to Niho tradition, such a person cannot do this Although Toyotomi unified the Niho, but if he did not become a general, the daimyo's loyalty to him would not be guaranteed. To put it more directly, because he was not a general, the daimyo had no nominal obligation to obey his rule.

Although I can suppress the princes, once I die, the heir who does not have the position of general cannot claim the loyalty of the daimyo in name, and the daimyo can legitimately fight for hegemony again (this was the case in the subsequent history of Ni Bang)

Since he is of low origin and lacks prestige, he cannot hold the position of general.

Then he had no choice but to gain prestige with great martial arts. After successfully conquering the continent, even if he was not born in Genpei, this unprecedented glorious achievement in history would be enough for him to establish a legal hereditary rule and lay the foundation for the eternal foundation of the Toyotomi family

As for courage, many Japanese pirates who plundered the Ming Dynasty met Hideyoshi. In their mouths, the Ming Dynasty's military equipment was extremely lax, and a few hundred Japanese pirates could often defeat the Ming Dynasty army (historical fact), which greatly strengthened Hideyoshi. confidence

In addition, it also has the purpose of diverting the contradiction between domestic daimyo