The author seldom shows any concern as to what similes and superlatives he used earlier while writing on other subjects, purposely allowing for some repetition and mild contradictions in ideas one can find in the Kural text. Despite knowing its seemingly contradictory nature from a purist point of view, Valluvar employs this method to emphasise the importance of the given code of ethic. Following are some of the instances where Valluvar employs contradictions to expound the virtues. The Kural is one of the most reviewed of all works in Tamil literature, and almost every notable scholar has written commentaries (explanation in prose or verse) on it. Some of the Tamil literature that was composed after the Kural quote or borrow its couplets in their own texts. According to Aravindan, these texts may be considered as the early commentaries to the Kural text. Dedicated commentaries on the Kural text appear about and after the 10th century CE. There were at least ten medieval commentaries of which only six have survived into the modern era. The ten medieval commentators include Manakkudavar, Dharumar, Dhamatthar, Nacchar, Paridhiyar, Thirumalaiyar, Mallar, Pari Perumal, Kaalingar, and Parimelalhagar, all of whom lived between the 10th and the 13th centuries CE. Of these, only the works of Manakkudavar, Paridhi, Kaalingar, Pari Perumal, and Parimelalhagar are available today. The works of Dharumar, Dhaamatthar, and Nacchar are only partially available. The commentaries by Thirumalaiyar and Mallar are lost completely. The best known among these are the commentaries by Parimelalhagar, Kaalingar, and Manakkudavar. Among the ten medieval commentaries, scholars have found spelling, homophonic, and other minor textual variations in a total of 900 couplets, including 217 couplets in Book I, 487 couplets in Book II, and 196 couplets in Book III. The best known and influential historic commentary on the Kural text is the "Parimelalhakiyar virutti". It was written by Parimelalhagar – a Vaishnava Brahmin, likely based in Kanchipuram, who lived about or before 1272 CE.