One consequence of running a twenty-day month against a twenty-sign day count is easy to miss and worth stating plainly, because it governs the whole shape of a Haab year. Since the Tzolk'in day sign repeats every twenty days and each full Haab month is exactly twenty days long, every month of a given year seats on the same day sign. If a year is seated on Kan, then 0 Pop, 0 Wo, 0 Sip and every other month seating in that year also falls on Kan.
That is why the Year Bearer is a property of the year rather than of the first day alone, and why the same four signs recur in the Postclassic Yucatec sources whenever a year is named: Kan, Muluc, Ix and Kawak. It also means a reader who knows the Year Bearer can work out the day sign of any date in that year from its Haab position alone, without consulting a table.
The pattern survives only within the eighteen full months. The closing Wayeb is five days long, not twenty, so it shifts the alignment by five positions and hands the next year a different bearer, five along in the twenty. Pop, seated first, is where each new alignment is announced.
Two things follow for a reader of dates. First, a Haab position on its own never identifies a year, only a place within one, so an inscription giving a Haab position without a Tzolk'in day is incomplete by design. Second, the Haab count is unbroken: highland Maya communities that kept the 260-day count through five centuries of colonial rule did not keep the Haab in the same continuous way, and its reconstruction rests on the inscriptions and the colonial record rather than on living practice.