This is an image of Chen style taijiquan's creator Chen Wangting jointly with Jiang Fa, in a classical teacher (sitting) - student (standing) pose. I have taken it from an undated brochure entitled Tai Ji Quan Hun (Taiji Boxing Soul) of the China Wen County Annual International Taijiquan Meeting Organizing Committee, chief editor Yao Daixian, which assembles information on Chen style including short portraits of numerous past and present masters jointly with business information on various local (food industry etc.) companies, (unnumbered) p.5. According to the note made below the image, the original is from Chen Qingzhou's family collection.
Presumably because this martial art was kept a family secret in the early days, the "generations" are defined, as I understand, beginning with the settlement of the Chen clan in Henan, i.e. not with the creation of Chen style taijiquan in the 1660s (cf. Gu Liuxin in Chen Style Taijiquan, p.3) by Chen Wangting, also called Chen Zhouting, who would arguably represent the style's 1st generation. Chen Wangting was "9th generation" of the Chen family in Henan, and so this is how counting is organized. Five steps down the line, Chen Changxing (1771-1853) who has passed on the art to the first non-family member Yang Luchan (1799-1872), also known as Yang Fukui, therefore is 14th generation and his student is 15th generation Chen style. By the same count, the current standard bearers are 19th generation masters. It is only recently that I have seen them as being declared 11th generation (which makes more sense in terms of a taijiquan lineage rather than a family lineage) in some publication.
Finding someone close(r) to the source still does not guarantee you will be taught everything you need since the person may not be willing to share the knowledge or simply not be a good trainer. But it usually improves the chances considerably. If you are unsure how to select your instructor, I believe the recommendations made by Mark Chen provide excellent guidance. (You should also note that many excellent coaches of different types of sports have not been champions as players, but possess very good trainer skills, while many strong players do not possess the skill to train anyone else. Martial arts are similar, only that often the highest levels of knowledge are not imparted to persons who have not excelled in practice.)
The sources for the two (mindmap and funnel) diagrams below, which are identical in content only arranged in a different way, are Chen Zhenglei's Zhongguo Chen Shi Taiji, pp.12-13; Chen Qingzhou's Chen Shi Taijiquan Gongfu Huicui, p.216; and Wang Xi'an's Chen Shi Taijiquan Lao Jia, pp.338-339.
