Tianguises are what guidebooks sometime refer to as "authentic weekly Indian markets." The word tianguis is mostly used in the central Mexican highlands. One feature of the tianguis is that many or most, if not all, items are exhibited in "unofficial" spots, such as is happening at the right, at the Sunday tianguis of Tepoztlán, Morelia. Tepoztlán's tianguis counts among its potential customers Mexico City's millions who need to drive only thirty-seven miles for great bargains, magnificent mountain scenery, and some clean air. In this "authentic tianguis," as one guidebook calls it, Indian pottery is as likely to originate in Guerrero or Puebla as from local kilns, and more than one huipil spotted in the "native textiles" stalls clearly came from Oaxaca.

In central Mexico, tianguises are typical of regions with large Indian populations. They are the one day a week when Indians come to town to buy and sell. Mexico's first mercados were tianguises. In fact, there is a good chance that many of the mercados encountered today began as tianguises -- at least those in Indian regions -- and have been operating more or less continually in the same neighborhood since long before the first Europeans came onto the scene.

Martin Diskin and Scott Cook, in a classic study of the mercados of the state of Oaxaca, looked at the origins of goods sold in the weekly tianguis of the town of Nochixtlán, about sixty-five miles northwest of Oaxaca City, on Highway 190. They found that many articles came from cottage industries in nearby villages. For example, cheeses were made in the villages of Etlatongo, Tinú, and Nochixtlán itself; candles were a specialty of the town of Yodocono; Zahuatlán specialized in fresh flowers, and; several artisans in Tilantongo and Tidaá carved wooden spoons. Nowadays tianguises also stock manufactured goods such as toys and transistor radios from the earth's far corners.

By no means are local Indians the only participants in typical Mexican tianguises. If a town is large enough to host a tianguis for surrounding smaller villages, it probably has paved roads leading to it, and these are open doors to enterprising wholesalers and retailers from far away. In Nochixtlán, merchants came from as far away as Puebla, 190 miles to the northwest, by often steep, curvy, mountainous roads. Sometimes fruit wholesalers came in trucks from as far away as the Gulf lowlands of Veracruz.

In permanent stalls in large and medium-size mercados, typically prices are fixed, perhaps written on a piece of cardboard, and that's usually the price one must pay. However, in a tianguis haggling may be productive; it may even be expected.

The rules of good haggling are rather simple. One should never disparage the item being considered. Try to ascertain by eavesdropping what others are paying for the item, then offer to pay a little less, and finally come up to the standard price. Foreigners are expected to pay more than local people.

Many towns hosting daily mercados also designate one day of the week as tianguis day. The mercado in Toluca is always busy, but on Friday's tianguis day business really takes off, with sidewalks and streets in the mercado area becoming extremely jammed.

Sometimes a town's weekly tianguis day is coordinated with weekly markets in nearby populations. For example, in the southern state of Oaxaca, at least three distinct cycles of coordinated weekly markets take place. One cycle takes place around Oaxaca City, another in the Nochixtlán area, and the third among towns in the Isthmus of Tehuantepec. Here is the cycle for the Oaxaca City area:

Especially in Mexico's most underdeveloped regions, people still may be seen arriving at the weekly tianguis after walking long distances along footpaths, or coming by horse. The mercado zone may be nothing more than a grassy or muddy open space where vendors simply choose spots on the ground, arrange goods there, and sit patiently awaiting customers.