Symbolism, Imagery, Allegory
To those of you out there that don't speak Japanese, "Banzai" sounds really similar to "Bonsai." Don't mix these two up, though: "Bonsai" refers to those adorable and beautiful little trees, and "Banzai" refers to highly trained and highly terrifying suicide attackers.
We'll let Chester explain it to you:
Japanese suicide attackers whose name, Banzai, was shorthand for the phrase… "May the emperor live one thousand years." They struck on foot, at night. When we heard them yelling, "Banzai! Banzai!" we knew we would witness a suicide, unless they killed us first. (12.15)
The Banzai make several appearances in Code Talker. At another point in the book, Chester says that:
[t]he Banzai adhered to the Japanese doctrine of blind obedience to authority, even when it meant their own death. (12.102)
These guys don't mess around. They're ordered to go out there and kill a bunch of Americans, knowing that they will die doing it, and they obey orders. On the island of Guam, where Chester and Roy Begay are stationed for part of the war, there's a big Banzai attack:
"The Japanese attackers were better organized than previous Banzai had been." (15.21)
Thankfully, the Americans are prepared for them, and by morning, "dead Japanese lay everywhere, 3,500 of them" (15. 24).
That's an unbelievable number of dead bodies, guys.
In Code Talker, the Banzai represent the terrifying face of the Japanese enemy. These Japanese don't just want to kill Americans, they want to scare them. Chester tells us that "the Banzai terrified U.S. troops all through the war" (12.101), and the anticipation of a Banzai attack was always "awful, demoralizing" (12.15).
The Banzai show us what a frightening enemy the Americans are up against in the Pacific. The Banzai are out not only to kill, but to terrify. They're not afraid of death. And how can Chester and his buddies defeat an enemy that isn't afraid to die?