Why did Japanese nobles put aside their differences and unite in 1274?

In 1274, Japanese nobles united primarily to confront the external threat posed by the Mongol invasion led by Kublai Khan. The looming danger of foreign conquest prompted various factions, including the samurai and regional lords, to set aside their internal conflicts and collaborate for the defense of their homeland. This unity was crucial in mobilizing resources and troops to resist the invasion, showcasing the need for solidarity in the face of a common enemy.