Trecena 18 opens on 1 Ehecatl, wind, under the patronage of Chantico, hearth goddess of Xochimilco, associated with volcanic fire and with precious things such as jewels, whose myth tells of a fast broken, eating roasted food during a fire ritual when abstinence was required, an offence for which the other gods transformed her into a dog, a punishment that gives her an unexpected mythic kinship with Xolotl, the dog headed guide of the dead who patronises Trecena 16 two weeks earlier in the count.
The wind week turns: its children read as changeable, quick of speech and loose of purpose, and Sahagun's informants took its days as unsettled, a reading that fits the wind sign's own restless character, moving everything and settling nowhere, more than it draws on Chantico's specific myth of transformation, though the theme of a rule broken and a consequence following sits comfortably beside a week already read as loose of purpose. A week for care with words and with promises, by the readers' own description, its patron's domestic, household scale of hearth worship, distinct from Xiuhtecuhtli's cosmic fire, gives this trecena a more intimate, personal register than the grander patronages elsewhere in the count.