In Chapter 29, what did the narrator say about something Kettle taught Fitz to give him protection from Skill?

The narrator spoke of an old game played among the Mountain folk. When Fitz and Kettle returned to the camp, Kettle was concerned that Fitz would be sought out by Regal's coterie, and he knew the three men were Burl, Carrod and Will. He tried to concentrate on Kettle's stone game, as she said it had been used by Skill people for years as protection.