Introduction Scholars of rhetorical sciences have focused their attention only on rhetorical issues in written literature and have neglected oral literature. It seems that attributing oral literature to the illiterate class, assuming it slang, and distinguishing between language and rhetorical issues are among the causes of this negligence. Unaware that oral literature has its own aesthetic structure and principles, this negligence is a disregard for a large part of the rhetorical capacity of language. Understanding this necessity, the present study has analyzed what is a kind of irony in popular literature that has not been mentioned as an enigma in any of the Arabic and Persian rhetorical books, while none of the allusions made in the rhetorical books are aesthetically comparable to such oral literature. The aims of the study are demonstrating the rhetorical capacities of Persian language in the field of oral literature, identifying this type of rhetoric in popular literature, comparing it with common irony in the rhetorical books and helping to correct the rhetoricians' point of view in this field. Therefore, this study intends to answer the following questions in this paper: 1. What is the rhetorical position of the enigma? 2. What is the difference between enigma in popular literature and irony of the subject in written literature? Research background Enigma exists in both oral and written literature. Most of the research in the past was devoted to the written form made by poets and was called Logaz. The oldest written definition of Persian language is related to Shams Qais Razi, who considers it a literary device and lists some features for it: "Slip is the meaning of the meanings when a similar problem is asked through a question. . . and this literary trick, in terms of meaning, is appropriate to the purpose and does not go into too many words and since it is far from false metaphors and metaphors, it is pleasant. And it will be useful for thought" (Qais Razi, 1995, p. 364,Blockbashi, 2009, p. 187). Chistan consists of a subject which consists of a descriptive element. Borjsaz (2009), in his article "Chistan, the first manifestation of the image of paradox in Persian poetry", without referring to Blokbashi's opinion, has introduced paradox as a rhetorical element that constitutes the poetic riddles of poets. Analysis In simile, we are faced with the constant presence of two sides (tenor and vehicle), and this is one of the fundamental differences between the structure of simile and metaphor. But in some literary tricks such as metaphor and irony, we are faced with to the hidden and suspending meaning,for example, in the explicit metaphor, we always have the tenor absence and in the irony, the absence of Makniyonbeh. This has caused the suspension of meaning. Attempts to reveal the hidden or absent element gives the reader or listener more pleasure, and this brings more rhetorical importance. Conclusion Enigma is same as irony, the one mentioned in the rhetorical books is the division of the irony into the validity of Makniyonbeh. This irony is very different from the ironies of rhetorical scholars, because in rhetorical sciences, adjectives help to know the subject and they do not have a special rhetorical beauty, while in describing the riddle, there are such things as metaphor, melody, coherence, paradox, taxi, contradiction and the like. Sometimes we see a mixture of irony and metaphor in riddles, and this in turn has created a special beauty so much so that the schools of rhetoric in this field seem incapable of describing, interpreting and justifying. Hence, public literature has its own beauties, which needs to be taken more seriously. The result of this study also indicates that the slip and the riddle, due to being ironic, need to be analyzed and examined in the rhetorical books instead of being studied in other resources.