How was the American woman living in Sapporo welcomed into the Japanese fold in the story retold in Chapter 27?

The American woman in Sapporo, whose daughter was enrolled at a Japanese kindergarten, was invited to a dinner by another mother, who also invited the teacher. Following the dinner, the hostess brought out a scroll depicting a violent, pornographic story. The American was confused and embarrassed by the incident, but nevertheless felt she had been invited into the Japanese "cultural sorority."