Fok Bo Chuen and Leung Jan both learned Wing Chun from Wong Wah Bo. When Leung Jan took sheltered in Foshan, he began teaching WingChun to Chan Wah Shun who later one became first master of Yip Man before his passing.
Meanwhile, Yuen Chai Wan traveled South to Vietnam to spread the sophisticated arts, and that was how the lineage in the video below was started.
As Yuen Chai Wan was also a true disciple of Shaolin Temple, he successfully integrated the Five Animals Form into this Wing Chun system (video below).
The Five Forms are known to be passed down from the 18 Lohan Palms Technique taught by Bodhidharma (527 CE).
The Vietnam Wingchun Branch also has the advanced 108 Movements Drill demonstrated in the video clip above that includes 6 kick forms and 8 knee techniques.
Now note that The Guangdong Wingchun branch has 160 movements with five different kicks and one knee technique. The Yip Man lineage has 116 movements (originally 140 but Yip Man consolidated the forms and removed what was not necessary or too deadly). Even though Yip Man’s 116 wooden dummy form is the most taught in the world, it had lost some of the most hidden techniques as they were not passed down to the next generation.
Consequently, these elements have made the Vietnam Wingchun fairly different to other branches that are more popular nowadays. Either way, the WingChun System has a very beautiful and solid history of its own.