The honored master
As the novel's title suggests, this story is about the legacy of an important karate master named Chojun Miyagi, the real life man responsible for the development of a karate style he named Goju-Ryo. The man appears in the context of this novel as a hero of the classical variety, now having come through the story of his life and having attained mastery. As an accomplished karate master, he takes on a student, the narrator of the novel, Kenichi Ota who accepts Miyagi as his master.
The fate of the finisher
The context of the novel is that the master has died, meaning that the course of the novel (set in flashback) will explain the growth of Ota as a student into the role his master used to hold. By the end of the novel, the reader expects to have seen an allegory unfold where student becomes the master. This is implied in the book's plot structure. Archetypally, that makes the narrator into a kind of "sacred finisher," who can take Miyagi's vision and see it to completion, perhaps, like Joshua and Moses.
The typhoon
The training that Miyagi gives Ota is not just stances, blocks, and strikes. He instructs his student to stand on the beach and stand still through an entire typhoon. The torrential winds and rains scrape his skin and he suffers against the enormous and powerful forces of wind, with lightning all around. What is this a symbol for? It is a symbol for Ota accepting life as it really is instead of insulating himself in naivete. By withstanding the storm, he burns off any illusion of weakness in himself. He knows exactly how strong he is. He is strong enough to survive.
Pearl Harbor
Pearl Harbor occurs as an ominous moment in the book where the master and student simultaneously realize that their life is about to be filled with war as the people suffer for the political decisions of their government. Before long, foreign nations are invading the island with devasting consequences. Ota has to endure a second storm, not the storm of nature, but the storm of human violence. He witnesses horror and carnage and becomes a true witness of the mid-20th century's violent streak.
The fall of old Japan
Before Miyagi's death, he and Ota were collaborating to come up with some response to the downfall of old Japan. Now that the city has been ravaged by war and economically drained by Japan's activity throughout WWII, there is very little hope in the public, and many people have devolved to absolute indulgence. The old Japan of social politeness and common courtesy has fallen into a chaotic survival zone where people have largely given up hope after the horrors they witnessed in war.
