I have read KC Chang s theory on this and I must say his ideas on Shang sucession seem very revolutionary, even if it was written more than 20 years back..because it very threatens what Sima Qian said in his Shiji.
Below is excerpt from regarding succession:
"汤崩,太子太丁未立而卒,于是乃立太丁之弟外丙,是为帝外丙。帝外丙即位三
年,崩,立外丙之弟中壬,是为帝中壬。帝中壬即位四年,崩,伊尹乃立太丁之子太
甲。太甲,成汤适长孙也,是为帝太甲。
Tang deceased, because Crown Prince Tai Ding predeceased him, Tai Ding's younger brother Wai Bing was installed as *King Wai Bing. Wai Bing died within 3 years of succeeding and his younger brother Zhong Ren was installed as *King Zhong Ren. Zhong Ren died within 4 years of succeeding. Yi Yin then installed Tai Ding's son Tai Jia as king. Tai Jia is eldest grandson of Tang..
KC Chang's theory, derived from the oracle bone records, however states the difference in lineage and even practices between the so-called 'Ding' line and the 'Yi' line after the 2 groups' most prominent 2 sub-groups. Because of this analysis, it implies that the reference of Tai Ding, Wai Bing and Zhong Ren as Tang( Da Yi)'s sons and Tai Jia as Tai Ding's son is almost certainly incorrect, because they belonged to different groups.
I am not entirelt convinced with KC Chang's theory... only thing I will agree is that every time there is a change from Yi line to Ding line and vice versa... there is a generation change. However, the solution may not have been so straight forward as KC Chang suggested... ( I am lost on any good ideas though)
Do we know (for certain) what system of succession they used during the Shang Dynasty? I recently read the book "Shang Civilization" by the late K.C. Chang, and in it, Chang presents his hypothesis, based on the names of the kings. The name of each king, and of each wife of a king, ends with one of the ten "celestial stems" ("day-signs"). (Apparently, in ancient times, a "week" that was 10 days long was used, & these were the names of the "days of the week".) Since a couple of these stems are much more common than others, Chang rejects the idea that they're based on day-of-birth or day-of-death. He classifies the stems into 2 groups, one including the stem "Yi" and one including the stem "Ding" ("Ting" in Wade-Giles). (These are the 2 most common stems in the names of Shang kings.) He notices (or it seems to him) that the stems appear in a kind of alternating pattern (alternating between the two groups). When a new king ascends the throne from a different/the next generation, his name contains a stem not from the same group as that of the previous king. But when a king from the same generation ascends the throne, his name will contain a stem from the same group as that of the previous king. (I think this situation is what Koolasuchus is referring to when he states that the king's [next] eldest sibling succeeds him upon his death.) In Chang's view, the 10 stems represent (10) smaller groups within the royal clan, which organized themselves into 2 main factions that shared power in the manner descibed above. Some parts of Chang's theory appeal to me, other parts bother me, and I have my own (alternative) hypothesis/idea/opinion about how Shang royal succession most likely worked...
However, I'd first like to hear from other posters, & hear their thoughts on the subject. (After all, this post is long-winded enough, & I don't want to be just "talking to myself". And perhaps I shouldn't assume that this topic is of interest to other posters. [If isn't, there's really no point in continuing it.]) So after this topic/post gets a few replies, I'll post again, & share my own ideas. If you think this post is either not clear enough or not brief enough, it's because I tried to make this post as brief as possible while making it so that someone who hadn't read the book I referred to could still get something out of it.
plain amateur, here to make mistakes, make a fool of ownself, and hopefully learn something in the process