From the Australian YKM site. http://www.ykm.com.au/history.php
The style of Yau Kung Mun finds its roots in the Northern Shaolin Temple from the monk Ding Ying who lived during the Tang Dynasty (618-907AD). Like many other monks at the temple, Ding Ying spent his life dedicated to perfecting himself spiritually and pugilistically. He was devoted to refining his martial art skills, focusing on what he saw as being the most effective techniques.
Through years of training he refined these techniques into a system, which was not given a name. To not name a system within the walls of Shaolin was not as strange as one might think. The monks were well known for their unsurpassed skills in martial arts. However, the temple was isolated and having an effective method of defence both against wild animals and those who would attack them was essential for survival. This need resulted in them opting to keep their most effective techniques and styles to themselves. A style without a name is a style that remains secret.
Violent warriors, seeking fame and greatness, would present themselves at the gates of the temple, challenging the renowned monks to come out and fight. Such challenges were taken seriously by the monks, as not only was their reputation at stake, but at times their very well being. In such situations, the disciples who were trained in the secret arts were chosen by the abbot to fight for Shaolin. By using techniques unknown to outsiders, they were able to defeat their opponents quickly, often within just one or two strikes. Thus, the style refined by Ding Ying was kept unnamed, only being taught to a select number of Shaolin monks to keep it secret from the outside world.
Life for the monks was drastically interrupted during the Qing Dynasty (1644-1911 AD). An imperial order was passed outlawing the practice of martial arts and in 1720 the Shaolin Temple was burnt to the ground. The few monks who were able to escape without being captured, scattered throughout China. One such monk was Dao Sang.
In his time within Shaolin, Dao Sang had used his proficiency in the unnamed style of Yau Kung Mun to defend the honour of the Temple against many challengers. He passed his skills on to the monk Wai Yat who taught Kit Loy and Sing Loy. Kit Loy then took the disciple Tit Yan, who became the first monk to teach the secret style to a layperson.
The name Tit Yan means ‘iron body’ demonstrating the perfection of his training. It is said that his strikes felt like being hit with iron bars, with punches penetrating the body of his opponent, causing external bruising, internal bleeding or breaking their bones. Such devastating power brings with it great responsibility.
Yau Kung Mun teaches that one must not learn how to destroy without first learning how to heal. Thus, disciples of Yau Kung Mun also learned how to heal through the application of bone setting and herbal ointments. Tit Yan was among the last of the true Shaolin Buddhist monks. As time went on, Tit Yan realised that the secret style of Yau Kung Mun would disappear with the last of the monks, unless it were given a name and its teachings passed on to the public.
Whilst in Southern Guangdong in the early 1900s, he accepted Master Ha Hon Hung, the first non-monk to be taken as a disciple in the style of Yau Kung Mun. After completing the training of Master Ha, Tit Yan left for Lo Fu Mountain near Huizhou, where he planned to live out his remaining years in solitude. Ha Hon Hung is the founder of Yau Kung Mun.