The secret fan is a symbol of the two main character's connectedness and history with each other. Lily and Snow Flower use the secret language that the women create to write special messages or memoirs on each slat of the fan, and then fan is passed back and forth throughout the girls lives. It is literally a pretty feminine piece, but as the fan becomes filled with their words, they are constantly reminded of their shared past, and no matter how many trials they face and how many ways their friendship is tested by deceit, treachery, and despair, they will always have the fan to remind them of they have been through together -- starting in their youth when their friendship was first "arranged." The secret language used on the fan is also symbolic of the strength of the women in the novel. It may have been a male-dominated society, but the women asserted themselves in this way and forged commitment and connections to create a support system for themselves.