Tonight, as he does almost every night, Roberto Corroy leaves his house in the Barrio de los Mexicanos and walks through the curving streets of San Cristóbal de Las Casas, his jacket zipped up to his neck, his hands stuffed into his pockets, and his guitar tucked under an arm. His thin-soled shoes slap the cobbles in hard, sharp smacks. The walk takes about 30 minutes. Roberto rarely speaks to anyone as he walks; instead, he occupies himself with worries about money and the future.

It is late enough that the windows of most houses are unlit, but not so late that the busier streets are not still busy. Bars and clubs are brightly lit and loud. Reaching the center of town, Roberto crosses the zocalo, the benches still harboring a few tourists despite the ear-chilling breeze, and mounts… More…