In the book Hiroshima, how did Mr. Tanimoto describe the Japanese Emperor's surrender and notice to the Japanese people?
The part that you are referring to happens at the very end of chapter 3. It's a fantastic bit of narration, because it conveys a huge sense of honor, veneration, and acceptance by the Japanese people.
Mr. Tanimoto starts off the section by saying a ". . . marvelous thing in our history happened Our Emperor broadcasted his own voice through radio directly to us, common people of Japan. . ." That opening line describes the absolute adoration that the Japanese people had for their emperor. He's more or less holy, and the people can't believe that they are hearing his voice. They are common people and he is the emperor.
A bit later in the paragraph Tanimoto says that some people began crying when they realized it was the emperor's voice. “What a wonderful blessing it is that Tenno himself calls on us and we can hear his own voice in person. We are thoroughly satisfied in such a great sacrifice." They are crying tears of joy, despite many of them being in large amounts of pain, because they have now heard the voice of their emperor.
The emperor's announcement was taken as a sort of sacrifice by the emperor as well. The common people consider it their sacrifice to Japan to endure their suffering, so it is a great honor to the people of Japan to know that the emperor himself is making the sacrifice to speak to them and announce the surrender.
Tanimoto also describes that the people of Japan heard the emperor's message and immediately, with no arguments or anger, followed the Emperor's commandment.
"Japan was defeated, they, of course, were deeply disappointed, but followed after their Emperor’s commandment in calm spirit, making wholehearted sacrifice for the everlasting peace of the world—and Japan started her new way,"