Edited and modified by the MuslimAnswers.net Team
بِسْمِ اللَّـهِ الرَّحْمَـٰنِ الرَّحِيم
There is some confusion in the minds of certain Muslims nowadays concerning the mass transmission (Tawaatur) of the Qur’an.
We heard of a question from one Muslim that was roughly something like this: “We say that we recite the Qur’an as per Hafs from ‘Asim (Rahimahumulla). From Hafs onwards, we know that there are many students so we can call this as Mutawaatir (mass transmitted). But what about from ‘Asim down to his immediate students, why do we have only two of them, Hafs and Shu’bah? Does this not mean that the readings are actually solitary? And if there are many other students, then why do we not find their names in the chains of recitation? And the same goes for [Imam ‘Asim’s teacher, Imam] as-Sulami (RA), if he had so many students, why is only ‘Asim (RA) well-known, and does this not mean that the common recitation with us is actually Ahaad? (Singly transmitted)”
Below is a response from a Shaykh who has obtained formal training in the sciences of Qira-aat (recitation of the Holy Qur’an) [slightly modified by us in order to clarify some points that may have been unclear in the original response]:
As salamu alaykum
You can find many different chains through other people. You don’t have to record every individual chain discretely. If the whole town or University is reciting in the same way you don’t have to record or name every individual chain of reciters. (As an example) you just say that the town of Westminster recites in this way, or the University of Cambridge recites in this manner.
Thus, the naming of the Imams has nothing to do with solitary or Mutawaatir narrations; it is just a label for that particular recitation. (We can take an analogy from mathematics) in the example of the x-y coordinates of a two-dimensional space: there are no real coordinates, but rather they are just labels. But (we also see that) the whole two-dimensional space exists in totality…. In the same manner, many reciters existed at the time with their own chains, but we need a label to specify each mode of recitation, and our label is just a narrator’s name from a particular Imam. Do not forget that these sciences developed afterwards, (and all the while) these recitations were already common in these regions, and they were recited and taught by the masses.
(As another personal) example, when I memorized the whole Qur’an, I had only two teachers for the whole Qur’an and some others had just one, and others had maybe more than 3-4 teachers, and so on. If you ask about my teacher I would name these two teachers to you, but I would reduce it to one as well as I recited the whole Qur’an to one of them or maybe to both of them. In his class there were about 10 students, we had about 20 classes in each school so there were twenty Imams and in this case we were the narrators of these Imams. Now, only one narrator became so famous because of certain traits he possessed, but this does not mean there was only one chain there.
As you can see from this simple example there were many chains individually as well as in groups. This is just one school, so imagine the situation considering that there were many schools like this in a city. During the time of the Prophet (SAW) there were about 9 different schools only in Madinah itself. So this gives you some sort of idea about the sheer size of the schools and the number of people during the time of the Followers (Taabi’een) and the followers’ followers (Taabi’ at-Taabi’een), and so on and on.
(Coming back to my personal example we see that) literally, from our school, there was only one person who became very famous in our region in Istanbul at the time (even though there were many more teachers in the region). I hope this example clarifies the misunderstanding, and is a valid answer to your question.
 That is, after the Imams in question (Rahimahumulla) had passed away.