Analysis of information sources in references of the Wikipedia article "Temple name" in English language version.
This was because nearly every emperor was given a posthumous temple name that either included the character zu 祖 or zong 宗, which were meritorious designations that entitled the bearer to receive offerings for the dynasty's duration (according to tradition, each dynasty was only supposed to have one ruler with the posthumous name of zu and two with that of zong).
Once a Shang king died he was awarded a posthumous "temple-name" employing one of the ten "heavenly stems" (tian gan, a later term) that were also used to name the ten days of the Shang week. Thus, we find ancestors being worshipped as Dajia (jia being the name of the first day of the week), Da Yi (yi being the name of the second day of the week), and Wai Bing (bing being the third day of the week).
This was because nearly every emperor was given a posthumous temple name that either included the character zu 祖 or zong 宗, which were meritorious designations that entitled the bearer to receive offerings for the dynasty's duration (according to tradition, each dynasty was only supposed to have one ruler with the posthumous name of zu and two with that of zong).
Once a Shang king died he was awarded a posthumous "temple-name" employing one of the ten "heavenly stems" (tian gan, a later term) that were also used to name the ten days of the Shang week. Thus, we find ancestors being worshipped as Dajia (jia being the name of the first day of the week), Da Yi (yi being the name of the second day of the week), and Wai Bing (bing being the third day of the week).
Once a Shang king died he was awarded a posthumous "temple-name" employing one of the ten "heavenly stems" (tian gan, a later term) that were also used to name the ten days of the Shang week. Thus, we find ancestors being worshipped as Dajia (jia being the name of the first day of the week), Da Yi (yi being the name of the second day of the week), and Wai Bing (bing being the third day of the week).