The Black Flags marched slowly through northern Tonkin, recruiting men to their standard as they went, and eventually set up camp just outside Son Tay, on the northern bank of the Red River.
Bendera Hitam berjalan perlahan melewati Tonkin utara, merekrut orang ke standar mereka saat mereka pergi, dan akhirnya mendirikan kemah di luar Son Tay, di tepi utara Sungai Merah.