Leung Jan

had chosen his sons, Leung Bak and Leung Chuen, as his successors. However, a neighbouring money changer, Chan Wa Soon, was greatly interested in Leung Jan's Kung Fu and began to spy on Leung Jan and his sons while they were practising. Leung Jan became aware of this very early in the piece, and intentionally modified the techniques he taught to his sons to reduce their effectiveness whenever Chan was watching.
Eventually, Leung Jan became impressed with Chan's keen interest, accepting him as a disciple. However, he continued to teach only the modified version of Wing Chun to Chan, because he feared that Chan would dispute the grandmaster titleship of Wing Chun with his sons after his (Leung Jan's) death.
This fear manifested itself after the deaths of Leung Jan and Leung Cheun, with Chan, a much larger and more powerful man, driving the surviving son, Leung Bak, from Fatshan. Leung Bak went to Hong Kong.
Chan began to teach the modified version of Wing Chun to selected students. Despite his reputation an popularity as a Kung Fu exponent, he only accepted eleven students. Then Yip Man, twelve years old at the time, came to Chan with three hundred pieces of silver, seeking acceptance as a disciple.