The Aztec tonalpohualli
A 260-day count we do not calculate — and the honest reason.
The Mexica — the people usually called the Aztecs — kept a 260-day count called the tonalpohualli, which means roughly the counting of the days. It has the same shape as the Maya Tzolkʼin: thirteen numbers turning against twenty named days, so a day reads 1 Cipactli, 2 Ehécatl, 3 Calli, and after 260 days the pair returns.
The names are Nahuatl and mostly different creatures and objects from the Maya list — crocodile, wind, house, lizard, serpent, and on through to flower. A newborn's day was read by a calendar priest, the tonalpouhqui, out of a painted screenfold book called the tonalámatl. Alongside the 260-day count ran the xiuhpohualli, a 365-day year of eighteen twenty-day festivals plus five days called nemontemi that closed the year.
There is no Aztec engine in Bokki. The tonalpohualli is not in our world atlas, it is not in our code, and no page of ours will hand you an Aztec day-sign.
This page exists because the gap deserves an explanation rather than a silence. A 260-day count from Mesoamerica sitting next to our Maya page would quietly borrow that page's credibility, and the two are not in the same position at all.
The Maya handed us something checkable: the Long Count, an absolute running tally of days carved on monuments. Fix one constant and every Maya date is fixed with it, and independent inscriptions can be used to test whether the constant is right. That is why our Maya engine can name 584283 out loud and check itself against seven published dates.
The Mexica kept no Long Count. To place the tonalpohualli on our calendar you have to tie it to a colonial-era record instead. The usual anchor is the fall of Tenochtitlan, which sources date to 13 August 1521 and record as the day 1 Cóatl in the year 3 Calli. From evidence of that kind scholars have built correlations that do not agree with each other — and the disagreements are not small print. They also differ over where the year began, and over whether the different altepetl, Tenochtitlan and Tetzcoco and Tlatelolco among them, were even counting in step. Two respectable sources can hand you two different day-signs for the same birthday.
That is a live scholarly argument, not a rounding error, and we have not done the work to take a side in it. Our rule is the same everywhere in Bokki: we ship a calculation when we can name the constant in the open and test it against evidence we did not choose to flatter ourselves. For the Tzolkʼin we could. For the tonalpohualli we cannot yet, and pretending otherwise would make every other number on this site worth less.
One correlation we can name in public, with the reasoning for choosing it written down where you can argue with it.
Several independent dated records to test it against — not a single anchor used twice and called agreement.
A clear statement of whose count it is: which altepetl, which reconstruction, and what the reconstruction assumes.
Day-sign meanings sourced to the surviving codices — Borbonicus, Borgia, Telleriano-Remensis — rather than assembled from whatever the internet repeats, with the discipline to leave blank whatever those sources do not say. That last one is the same rule that stops us inventing meanings for the Maya Lords of the Night, whose names are simply lost.
The two counts are relatives. Several signs line up in sense — Cipactli with Imix, the crocodile and the earth-monster; Ehécatl with Ikʼ, the wind — and the 260-day rhythm is shared across Mesoamerica. But the names, the imagery and the ritual are Nahua, not Maya, and whether the two counts landed on the same day as each other is part of the same unsettled correlation question. So we will not print a Maya date and let you read it as an Aztec one. If you want the count we can actually verify, it is the Tzolkʼin.