Writer and director Quentin Tarantino has stated multiple times Cirio H. Santiago's movies influence on him. In this movie you can see that huge influence, in what would later be used on Kill Bill: the main character being betrayed by his friends and being left to die; him surviving and swearing revenge; being educated on Samurai culture and preparing his revenge, among many other elements.
Part of the movie plot - the japanese soldiers being stranded on an island 20 plus years after the World War ended unaware Japan had surrendered, thinking it was America propaganda in order for them to be imprisoned - is largely inspired on a real life story, of Hiroo Onoda and his men, who were a group of Japanese soldiers that were allocated to a Pacific island, where they lived on the deep florest and developed guerrilla warfare for almost 30 years, unaware the Japanese Emperor had surrendered and World War II had ended. This true story would later be adapted into a film "Onoda"