Minamoto no Takaakira (914-983), tenth son of Emperor Daigo, was demoted to commoner status as the “Daigo Genji” line. A leading scholar of court ceremonial, he authored the Saigūki, a foundational reference for Heian court ritual. As left minister he became the father-in-law of Prince Tamehira, a leading candidate for the throne. In the 969 Anna Incident, Minamoto no Mitsunaka denounced him for plotting Tamehira’s enthronement, and the Fujiwara had him exiled to Dazaifu within the day. He returned in 972 but never recovered political influence. The incident completed the Fujiwara purge of rival lineages and established their two-century monopoly over the regency.