What was Operation Rio Blanco as noted in the biography, Marine Sniper?

Operation Rio Blanco involved elements of the U.S. Marines, the ROK Marines, and the ROK Army, capturing area in the region along Song Tro Khuc. The operation took place in November, 1966, and included at least twelve snipers. Land, Burke, Hathcock, and other snipers participated in the operation. The time period is considered during Chapters 10 and 11 of the text, and Hathcock is based on Hill 263.