Summarize The document contains sketches showing locations and developments of various battles conducted by the 31st Regiment, 2nd NVA Division. It includes information on attack strongholds in Trung Phuoc, ambush at Cau Bon, raid on Thay Vien, emplacement of an OP and maneuvers of RVNAF/PWMF Armored vehicles, and an attack on an "enemy" element near Phu Phong Vill. Troop strength and weapons are also recorded.