Who is Yu-sung from Women of the Silk and what is their importance?

Yu-sung is the mother of the main character, Pei. Yu-sung was born into a family that was not wealthy in material but rich in happiness. Her mother kept a clean home, and her parents were very loving. Yu-sung's parents arranged a marriage for her via the village matchmaker. She was sent to marry her husband, Pao, while they were still children. Pao's family was very different from her own. They were descendants of the Hakka tribe and spoke a different dialect than that to which Yu-sung was accustomed. Consequently, they communicated very little and Yu-sung was lonely. Pao was also rough with Yu-sung. Yu-sung committed herself to cleaning their home, which in her impression, Pao had failed to do, and raising the children they conceived. Unfortunately, many of the children she delivered died in infancy.