What is the setting in the memoir, Homesick: My Own Story?

In the preface to Homesick, Fritz remarks that "although this book takes place within two years—from October 1925 to September 1927—the events are drawn from the entire period of my childhood ... they are all, except in minor details, basically true." Family photographs accompany the text and make the story more personal and real. Since some knowledge of the historical period is helpful for an understanding of the book, Fritz also provides a brief section titled "Background of Chinese History, 1913-1927."