[Note 1] The attackers were supported by the gunboats Pluvier, Léopard, Fanfare, Éclair, Hache and Mousqueton from the Tonkin Flotilla, under the command of capitaine de vaisseau Morel-Beaulieu.

[3] On 31 August the village of Palan, bombarded from the rear by the gunboats and attacked frontally by Berger's battalion, was captured without difficulty, and its defenders fled in disorder along the dyke.

At dawn on 1 September the column advanced along a two-metre wide dyke which ran along the bank of the Day River towards its main objective: Phong, a principal point on the road to Sơn Tây.

Although they made a lot of noise, yelling and waving their flags and beating their gongs and drums in a warlike manner, they showed little enthusiasm for actually fighting.

The Black Flags had evacuated the pagoda before the French arrived, and fallen back to the centre of their position, which lay behind the earth embankment of a dyke four hundred metres further on.

Eventually Bouët ordered Berger to assault the enemy centre, and sent over Taccoën's company from Roux's battalion to reinforce the attack.

The three attacking companies advanced across the 600-metre gap between the pagoda and the dyke in skirmish order through breast-high water, holding their rifles above their heads to keep them dry.

But the attack was so rapid that around fifty Black Flags, who had been lying on their backs asleep, did not have time to get to their feet, and were pinned to the ground with bayonet thrusts.

[4] While Berger was storming the centre of the Black Flag line around Phong, Roux attacked and routed the Vietnamese on the left, burning down the straw huts nestling in the middle of the bamboos.

Before the scandalised French could stop them, the jubilant Yellow Flags beheaded the corpses, stuck the heads on long bamboo poles, and planted them on the embankment of the dyke.

But public opinion in France was anxious for a resolution of the Tonkin Campaign, and although the French now installed a post at Palan, enabling their gunboats to patrol the Red River as far as Sơn Tây, this limited advance hardly satisfied Bouët's critics.