"Yoshikado-sensei said, 'They're still there. Spear them! Spear them!' and it was really fun. I was tired, but I realized that even one person can kill a lot of the enemy."

So wrote Mihoko Nakane, a 10-year-old Japanese girl, in her diary in July 1945. She was describing the hand-to-hand combat training she and her classmates were getting for the "decisive battle" to be fought if and when the U.S. and its allies invaded mainland Japan.

It's one of many sobering vignettes recounted in Samuel Yamashita's recently published "Daily Life in Wartime Japan." Drawing on more than 100 wartime diaries, Yamashita offers snapshots of how Japanese civilians mobilized for war, celebrated their military's initial stunning victories, obeyed (or resisted) their government's edicts, and endured the tightening circles of hardship that culminated in the collapse of the Greater East Asia Co-Prosperity Sphere.

Yamashita, a professor of history at Pomona College (where he and my father were colleagues), didn't intend to add to the brouhaha over whether President Barack Obama should apologize to Japan on his planned visit to Hiroshima next week -- the latest installment of a seven-decade debate over whether the U.S. was justified in dropping atomic bombs on Hiroshima and Nagasaki. Instead, Yamashita wrote it largely to fill a gap in the war's English-language historical record.

Yet Yamashita's effort to surface wartime Japanese civilian accounts illuminates that debate, providing real-time evidence of how willingly most Japanese embraced the regimentation and sacrifice of the war effort. In so doing, his book lends weight to the idea that a massive, terrible shock was necessary to convince Japan that even an envisioned "suicide of 100 million" civilians -- to borrow a phrase used by military officials in 1945 -- would not achieve a negotiated conditional surrender, much less victory.

Japan had been girding its people for war since well before the attack on Pearl Harbor. As Yamashita documents, popular indoctrination, restrictions on media, and controls on raw materials were ratcheted up from the mid-1930s onward, especially after Japan's 1937 attack on China. In 1940, the government took over food distribution, with the Home Ministry using new community councils and nearly a million neighborhood associations to oversee rationing, sell war bonds, organize scrap drives and rally the populace.

As Yamashita writes, these new bodies "not only subtly shaped the behavior of wartime Japanese but also served to keep them in line." Diary entries show their almost daily intrusions, whether in the form of air raid drills, work brigades, or feverish troop send-offs.

As war crept closer to the homeland, the government encouraged families to send their children to the countryside to escape bombing raids; by war's end, nearly 1.3 million had been evacuated. Yet the government had more than safety in mind. As Yamashita writes, it was also intent on transforming the transplanted youngsters into what it called "splendid little citizens" who embodied national virtues.

Their textbooks extolled Japanese as the politest people in the world and Japan as "the only divine country." Children were instructed to keep diaries, which administrators regularly inspected. They wrote "comfort letters" to soldiers at the front, and greeted processions carrying the boxed ashes of war dead. Teachers imparted the "national citizens' quotation of the day" and added their own commentary, along the lines of "What will happen with the attacks of the foreign devils? We must harden our spirits and resolve to launch a great counterattack."

As Japan's depleted military resorted to "special attack units" (the infamous kamikaze pilots), teachers lionized these suicide squads as "divine spirits" who had "reached the territory of understanding." The evacuated children's long hikes to forage for firewood, bamboo shoots, edible roots, frogs and grasshoppers gave way to exercises in spear-fighting, swordplay, and hand grenade-throwing. On these trips, some of the teachers would break away to learn how to fly gliders to be loaded with explosives and flown into Allied ships.

The last third of Yamashita's book is a close reading of 24 diaries and 25 "last letters" of Japan's kamikazes. As Yamashita notes, the special attack units were not an ad hoc initiative, but something discussed "at the highest levels" of Japan's military leadership, with a strong emphasis on the pilots' spiritual training, especially the inculcation of "self-cultivation" and "self-sacrifice." As one kamikaze pilot wrote in January 1945:

"I exist because my country exists; without a country, I would have no family. If there is life, there is death. Joining a special attack unit and 'shattering the jewel' is, to me, the highest site of death."

In the last year of the war, Yamashita writes, "this same discourse began appearing in the government-controlled mass media." Japan's biggest cities were by then fields of ash and rubble, their residents reduced to near-starvation. But despite isolated acts of subversion and resistance, "most Japanese did what their government urged them to do; namely, to prepare for the 'decisive battle' that would take place when the enemy invaded the Japanese home islands in the fall of 1945."

That decisive battle never took place, in large part because of the devastating atomic bombings of Hiroshima and Nagasaki in August 1945. At least, that's Yamashita's view; he reminded me that Japan's military-dominated Cabinet was still arguing whether to surrender after the Hiroshima bombing when news arrived of the bombing of Nagasaki. Others point to different reasons for Japan's surrender, notably the sudden decision by the Soviet Union to enter the war.

After reading this book, though, I found it hard to argue with what Yamashita told me: "Had the bombs not been dropped, and had the Allies invaded as they were planning to, it would have been horrible beyond belief." The numbers support him: As many as 150,000 civilians may have perished in the battle for Okinawa alone, for instance. Never mind the Allied servicemen who might have died -- including perhaps my father, a battlefield interrogator in U.S. naval intelligence who went on to join a cadre of postwar Japanologists. Spare a thought for the Japanese boys and girls training to throw themselves under advancing U.S. tanks with bombs strapped to their chests.

Nearly two and a half million Japanese died in World War II. But thanks in part to President Harry Truman's decision to use atomic weapons, Mihoko Nakane wasn't one of them.