A special, and not very well-known topic, even amongst scholars according to our teacher Mohammed Daniel ḥafiẓahullah, during one of his lessons with regards to the hadith – sciences, is the topic of the so called ‘thulāthiyyāt’ traditions (aḥādīth) or
narrations about the Prophet (upon him blessings and peace).
Thulāthiyyāt traditions are those specific traditions that only have three narrators (in the chain of narration c.q. sanad/isnād) -also called ‘links’ in Orientalist hadithliterature or discourse 1 – between the one who relates the tradition (in other words: the fourth person in the chain of narration) and the Prophet Muhammad (peace and blessings be upon him). These three narrators would consequently be a Saḥābi, a Tābi’i and a Tābi’i at-Tābi’i. As for the one who relates the tradition: this mainly concerns a well-known name/scholar in the field of hadith i.e. a compiler or author of a major and well-known hadith – collection (in the past) like Ṣaḥīḥ al-Bukhārī, Ṣaḥīḥ Muslim and so on.
See here: Thulathiyyat