(Left: La Triomphante, one of the French warships that attacked Danshui.)
Prior to the Battle of Fisherman's Wharf, there were already about 1,000 regular army in Danshui under the command of Generals 孫開華Sun Kai-Hua (an officer of the 湘軍Xiang Army, commanding the 擢勝左營) and 章高元Zhang Kao-Yuan (of the 淮軍Huai Army).
Sun, by all accounts, was an extraordinarily brave man, treated his solders well and was loved and respected in return. He was also a relatively uncorrupted official, a rarity among those who were sent to Taiwan to govern (or steal, i.e., in the form of officially sanctioned bribery). His successful defense of Danshui was later maligned by 劉銘傳Liu Min Ch'uan. In the latter's report to the Qing Court, General Sun was falsely accused of leaving the construction of the gun batteries in Danshui unfinished. Liu himself, after the defeat in Keelung on Oct 1, 1884, retreated to Taipei in disgrace, roughed up by the locals residing in Manka (now Wan-hua). And yet he claimed victory in his official reports. Liu later became the Governor of Taiwan and Sun was sent back to lead an army in Hokkien. And after a series of demotions, he died on the job in 1893, at age 55. All his honors were restored posthumously, however.
At the beginning, in anticipation of the French's attacking northern Taiwan, Liu did send 2,500 men to guard Keelung (where the French indeed made their first move on Aug 5, 1884), while retaining another 2,500 as the reserve to station in Taipei - with 1,000 later sent to Danshui.
The military build-up in Danshui continued unabated throughout September, 1884:
Sep 8: After Liu Ming Ch'uan inspected the artillery defenses of Danshui, 100 artillerymen were quickly dispatched from Taipei to man the coastal batteries.
Sep 17: About 500 militiamen (similar to the Minutemen of Massachusetts in the battles of Lexington and Concord), organized by a local para-military leader 張李成Tio Li-xieng congregating in the Customs Office area in Danshui. They were probably either Mountain Hakkas dressed as the Aborigines or the actual Aboriginal warriors (the clothing suggested either 平埔番Pinpuhuan or the 泰雅Atayal tribesmen), or a mix of both.
Sep 20: 550 and 50 men on board of British commercial transport ships Waverley and 萬利Wan-li, respectively, arrived in Danshui. Because of the typhoon, after 100+ had disembarked, Waverley went out to sea to sit out the storm but eventually returned to Shanghai. And the Wan-li entered the port on Sep 21 to let off the "passengers". These men were actually soldiers in plainclothes to avoid interception by the French. Their weapons had already been shipped in through the eastern and southern ports of Taiwan.
Sep 26: French gunboat the Vipere drove away the transport Sea Dragon because on board were 150 suspiciously looking men arriving from Shanghai. They were in fact the third reinforcement contingent sent from China.
Sep 27: The transport 華安輪Hua-An with 300 men on board was forced out to sea by the Vipere. It landed in 新竹Hsin-Chu the next day.
The defenders of Taiwan during the Sino-French war were either from 安徽(An-huei) in eastern China (the 淮軍Huai Army) or 湖南(Hunan) in south-central China (the 湘軍Xiang Army) . In Danshui, most seemed to be 湘軍, or 湖南勇 (O-Lam Youn) from 湖南善化縣. The locals called them 河南勇 (Ho-Lam Youn), a confusion resulting from the language barrier - the many different spoken dialects in town did not help. These men turned out to be a hardy bunch. Even the most severely wounded after being cared for at the Mackay Clinic for a few days ran back to the camp - to the amazement of the physicians. And one or two wounded tried to pay the doctors, with the last dollars that they had, for services rendered (politely declined by the MDs). The doctors in attendance were Dr CH Johansen from Germany and Dr Browne, the ship surgeon of British gun boat Cockchafer. About 200 soldiers were treated by these two gentlemen.
The bombardment of Danshui started at 10AM on Oct 2, 1884. By then the defense was ready.