What is the main conflict in The Makioka Sisters by Junichiro Tanizaki?

The Makioka Sisters is the story of four sisters in a wealthy Japanese merchant family that is in declining fortune in the years leading up to World War II. The novel focuses on the viewpoint of Sachiko, the second oldest sister, who with her husband Teinosuke play an increasingly important role in the family's affairs as the oldest sister Tsuruko and her husband, Tatsuo the head of the "main house" of the family, move away from the family's seat in Osaka to Tokyo. Meanwhile, Japan becomes increasingly hostile toward China as it prepares for war. The Makioka family sees many of its European acquaintances in Japan leaving for home as the situation in Europe moves toward war.