Flags of our Fathers, the first part of Clint Eastwood's two-part, two-sided saga of the battle of Iwo Jima, was about the nature of heroism, while the second part, Letters From Iwo Jima, is about the nature of survival. Japanese men of World War II were soldiers but they didn't necessarily soldier on when things looked bleak; the codes of honor that had governed Japanese warfare for centuries demanded they kill themselves when all was lost rather than surrender to the enemy. The men of Letters From Iwo Jima must decide whether to honor tradition or themselves, to choose between life and honor, and as Eastwood's film illustrates, neither are easy choices.

None of the actors from Flags, which explored the American perspective on Iwo Jima, appear in Letters. No attempt is made to link the stories, and just as the Japanese were barely present in Flags, the Americans rarely appear in Letters. Considered as a whole, the two don't delve into why we fight so much as how. Both are about the sacrifices we make -- culturally, ideologically, and morally -- in war, how winning a battle can involve losing something else, and vice versa.

In Flags, the Japanese forces were the epitome of an absent presence, never seen but always lurking around a corner, inside a foxhole, behind a machine gun turret; with their bunkers and barracks and maze of underground tunnels, it seemed as if they were swarming everywhere at once. In Letters we see the truth: The apparitional presence of the Japanese stemmed largely from the fact that, vastly outnumbered, undernourished and with limited weaponry and tactical support, they were essentially a bunch of walking ghosts. Already defeated everywhere except in their own minds, Iwo Jima's commander General Kuribayashi (Ken Watanabe) receives orders to last as long as he can with whatever means he can muster. There are no reinforcements coming. By way of pep talk, he tells his men, "Do not expect to return home alive," and that no one is permitted to die until they've killed at least 10 enemy soldiers.

With defeat never less than completely assured, the film's first act, where Kuribayashi attempts to marshal the troops in preparation for the American arrival at Iwo Jima, doesn't quite click. But as soon as the Marines land on the beach and the Japanese men are literally waiting for death, Letters From Iwo Jima becomes nearly as effective as its predecessor. The most moving story involves an officer named Nishi (Tsuyoshi Ihara) a former champion horse rider who competed in the 1932 Los Angeles Olympics; knowing that the propaganda about America is largely false, he serves his country faithfully, selflessly and tragically to the bitter end.

When Nishi transfers to Iwo Jima and presents himself and his horse to Kuribayashi -- who has also spent time in America -- the general tells Nishi that he yearns for the days when soldiers rode into battle on a horse. You can sense Eastwood probably does too, in more ways than one; the director suggests nostalgia for a time of simpler warfare but also a time of pat morality in movies, when a man (say, Clint Eastwood), could ride into town on his horse, mow down the villains and ride off to the next fetid cesspool of the west. Letters From Iwo Jima and Flags of our Fathers both yearn for that simpler time and acknowledge its central fallacy: that such an era only existed in our minds out of an ignorance manipulated and controlled by governments who needed such illusions to perpetuate their wars.

Political undertones aside, Letters From Iwo Jima is a beautiful, tragic story of a few Japanese soldiers who saw through that ignorance and dared to question the tradition of suicide in the face of surrender. Much of screenwriter Iris Yamashita's story is told from the perspective of a simple baker named Saigo (Kazunari Ninomiya), who promised his wife and unborn child that he would return to them when the war ended. He fights the battle of Iwo Jima not to win but to survive, even as his countrymen murder themselves around him (in one horrific scene, Saigo stumbles into a cave of soldiers who communally agree to commit suicide by grenade). There are quite a few profound moments in Letters From Iwo Jima, but none linger in my memory more strongly than a moment late in the film when Saigo and Kuribayashi meet again and the general marvels that the lowly infantryman has lasted this long. "You," he tells Saigo, "are quite a soldier," knowing that the baker has done nothing to help his country and everything to help himself.

The title refers to a series of flashbacks and narrations that blend with the battle footage to show the backgrounds of the various main soldiers framed as letters they have written to their families back home. In what is perhaps the most important ideological passage of either of Eastwood's Iwo Jima movies, Nishi shares an amicable conversation with a captured American soldier. After the American dies, the Japanese men discover that he wrote letters home to his family too.