The origin of this custom is the long-standing feud between Koxinga and Ming-Cheng turncoat 施琅Shi-Lang. Koxinga killed Shi-Lang's father and brother (1650) as a punishment for Shi's disobeying an order not to execute 曾德Tseng-Der. And years later (1683), Shi ended the Tung-Ning Dynasty on Qing's behalf. The restriction of marriages between the two families was originally limited to 泉州Chuan-chou area but later extended to all of Taiwan.
There is another marriage ban known only to the Koxinga-Cheng clan, i.e., never marry any 黄Huangs. It is not entirely clear why this practice; although it appears to be related to the conniving acts of another Ming-Cheng turncoat, 黄梧Huang-Wu.
[Above: The family temple of 黄梧Huang-Wu in 平和Pin-Ho County, 漳州Chang-chou]
A young 黄梧, after assassinating the corrupt head of his home county, joined Koxinga's forces in Amoy in the 2nd month of 1644 and received a mid-level appointment with 200 taels of silver as bonus. He distinguished himself in many battles against the Qing and rose through the ranks until 1650 when he found himself in a delicate situation.
When Koxinga ordered the arrest of Shi-Lang, Huang's superior 蘇茂Su-Mao actually allowed Shi to escape. Su-Mao was later killed and by implication, Huang was also found guilty and fined heavily (in the form of a contribution of 500 sets of armors). Huang subsequently became quite concerned of his own safety. In a transfer of duty to 海澄Hai-chen, the main logistic center of Ming-Cheng and the gateway to Amoy and Kinmoy, Huang decided to defect to the Qing and handed over the fort. For this act, he was awarded the title of Duke of 海澄. In the 3rd month of 1657, the Qing Court further honored his ancestors and provided funds to build his family temple (see above). In return, he plotted enthusiastically for the downfall of Koxinga. He trained a naval force (1658) and defeated 周端, Koxinga's commander in Hokkien (1660), recommended Shi-lang for the eventual invasion of Taiwan. And among his many proposals submitted to Qing Court was the 《平海五策》[The Five Strategies for Conquering the Sea] with one of them purely for personal vendetta:
四． 成功之祖先墳墓在各處，叛臣賊子罪誅及九族，何況其祖乎？應加以遷毀，慕露殄滅，使其命脈斷，則種類不待誅而自滅。[No 4: The nine relations of rebels/traitors are all punished by death, how can their ancestors be exempted. Koxinga's ancestral graves everywhere must be removed and destroyed and the remains exposed. This way, the whole lineage will be interrupted and the clan self-destructed without the need of exterminating them at all.]
In the 10th Month of 1662, 黄梧 submitted a confidential proposal to have Koxinga's father Cheng Zi-Long [and family members] executed.
Both proposals were accepted and carried out. Koxinga could not believe the news of his father's and brothers' death when he first learned of it in Taiwan. Soon after, he passed away, in apparent anguish.
This was not the end of the story, however.
In 1674, 耿精忠Geng Jing-Chung revolted against the Qing and 黃梧 seemed to have joined 耿 in this revolt (still being debated if this ever happened); although Huang soon died of a painful illness. In any case, his son 黃芳度Huang Fang-Du took over the defense of 漳州, then disputed with and fought against 耿. This was followed by surrendering to Koxinga's son Cheng Jing [who was then on a mission to recover the mainland]. 黃芳度, however, double-crossed Cheng Jing by secretly allying with the Qing and refused to host Cheng Jing in 漳州. Cheng Jing, sensing Huang's treachery, attacked the city and entered it when Huang's second-in-command 吳淑We-su opened the gate. Huang killed himself by jumping into a well at Kai-yuan Temple 開元寺. Cheng Jing ordered 黃梧's coffin opened and 黃芳度's body recovered, and both of them beheaded. Thirty some members of the Huang family were also executed.
One branch of the descendants of the surviving Huangs migrated to Taichung in 1878, and another to Ilan.
This specific order for the Koxinga-Chengs not to marry any Huangs is still in full effect today.