What is the meaning of: thulathiyyat of Imam Bukhari?
This is a term used to refer to a chain that only consists of three narrators between the author and Rasulullah (sallallahu ‘alayhi wasallam).
In general, the Muhaddithun value the shorter chain over a longer one, on condition that it is authentic.
Imam Bukhari (rahimahullah) has twenty two such Hadiths (thulathiyyat) in his book, which is the most from among the authors of the six famous books (sihah sittah).
(Also refer: Hadiyyatut Darari of Shaykhul Hadith Moulana Fadlur Rahman A’zami, pg.75-76)
And Allah Ta’ala Knows best,
Answered by: Moulana Muhammad Abasoomar