Maqlub (inverted report)

"Knowing the maqlub" is the twenty-second type in Ibn al-Salah, who defines it by example: a well-known hadith from Salim, say, is assigned instead to Nafi', so that it becomes rare and sought after. ¹

Ibn al-Salah relates that when al-Bukhari came to Baghdad, a group of hadith scholars gathered before his session and took a hundred hadiths, inverting their texts and chains — giving this chain's text to another chain and this text's chain to another text — then came to his session and put them to him; when they had finished he turned to them and restored every text to its chain and every chain to its text, and they acknowledged his excellence. ¹ Inversion here was a test of a hadith scholar's memory, not a narration meant to transmit.

Another example, which also illustrates a hidden defect, is what Ishaq ibn Isa al-Tabba' related from Jarir ibn Hazim from Thabit from Anas from the Prophet ﷺ: "when the prayer is called, do not stand until you see me". ² Ishaq said: I went to Hammad ibn Zayd and asked him about it, and he said: Abu al-Nadr was mistaken; we were all in Thabit al-Bunani's session with Hajjaj ibn Abi Uthman, and Hajjaj al-Sawwaf told us this from Yahya ibn Abi Kathir from Abd Allah ibn Abi Qatada from his father from the Prophet, and Abu al-Nadr thought it was among what Thabit told us from Anas — Abu al-Nadr being Jarir ibn Hazim. ²

Inversion is a kind of error in chain or text, close to the mudtarib and the mudraj, and it borders on forgery when a narrator does it deliberately to produce something rare, as in the Salim–Nafi' example. ¹