More than 40 years after its sponsorship of Bjorn Borg began in 1975 ... to its roots in a way—the roots of a grass-court giant's family tree.

It was an odd place for a Swedish family, and an 18-year-old ... knows what kind of convoluted logic or mystical yearning: Bjorn Borg. Borg refers to Honsai as “the Professor.” ...