Having thus cleared the district due north of Wusieh, Gordon proceeded against the main Taeping position at Chanchufu, north-west of that place, and on the Grand Canal. Here Chung Wang had fortified thirty stockades, and commanded in person. On inspecting it, Gordon found it so strong that he summoned up his troops from Liyang, and it was not until 22nd April, ten days after Waisso, that he had collected all his force of 4000 men for the attack. On the very day he accomplished this the Imperialists alone attacked some stockades outside the West Gate, and carried them by a heavy and unnecessary loss of life. Their defenders, instead of retreating into Chanchufu, fled northwards to their next possession, at Tayan. The same night part of the garrison left behind made a _sortie_, but Gordon was apprised of it, and it was easily repulsed. The next day he captured all the stockades on the southern, or, more correctly, the western side of the Canal, but the Taepings still held a strong stone fort on the opposite side, which defied all the efforts of the Imperialists. Two hundred of the Liyang corps gallantly crossed the Canal in boats, forced open the back door of the fort, and carried it at a rush. With this success all the outworks of Chanchufu were taken, and the town itself closely besieged. Gordon then proceeded to plant his batteries opposite the point he had selected for attack, but a regrettable affair happened in the night, when the picket on guard fired into the party working at the battery, and killed Colonel Tapp, an excellent officer who commanded the artillery of the force. This mishap was quickly followed by others. The Imperialists under their own generals wished to get all the credit of the capture, and attacked several times on their own side, but always without obtaining any advantage. Nor was Gordon himself more fortunate. After a severe bombardment, to which the Taepings made no reply, Gordon assaulted on 27th April. His men succeeded in throwing two pontoons across the ditch, twenty yards wide, and some of his officers reached the wall; but the Taepings met them boldly with a terrific storm of fire-balls, bags of powder, stinkpots, and even showers of bricks. Twice did Gordon lead his men to the assault, but he had to admit his repulse with the loss of his pontoons, and a great number of his best officers and men. Ten officers killed and 19 wounded, 40 men killed and 260 wounded, represented the cost of this disastrous failure.