Mariachi is a 7-to-12-piece ensemble tradition from the state of Jalisco in western Mexico: two to six violins, two trumpets, the high-pitched five-string vihuela strumming chords, the round-backed six-string guitarrón anchoring the bass, and a lead vocalist backed by ensemble vocals. Every player wears the ornate silver-buttoned charro (Mexican cowboy) suit; that visual uniform is nearly as constitutive of 'mariachi' as the sound. Time signatures shift between 3/4 waltz, 2/4 polka, 6/8 huapango, and the slow ranchera ballad, often in the same set. Singers punctuate the music with the grito — a high, sustained shout of exhilaration that turns any song into a public celebration.

Mariachi grew in the nineteenth century out of small string-based folk ensembles in Jalisco's Cocula region. The first commercial recording (Cuarteto Coculense, 1907) marks the transition to a professional format. In the 1930s the radio-and-cinema golden age turned Jorge Negrete and Pedro Infante into the 'singing charro' archetype. The 1945 formation of Mariachi Vargas de Tecalitlán (in a lineage descended from an 1897 ensemble in the town of Tecalitlán) codified the modern instrumentation; for the eighty years since, Vargas has served as the world reference mariachi. After the Revolution (1910–20) the state's mestizaje policy explicitly enlisted mariachi as the national sound of Mexico.

Listen first to the guitarrón — its wooden resonating body produces a round, un-electrified bass unlike anything a standard bass guitar sounds like. Then the two trumpets, which unison in thirds or sixths to produce mariachi's signature fanfare quality. Above all, listen for the grito — the sung 'ay, ay, ay, ay' shout at the start of songs or before choruses — which converts a piece of music into an occasion. Vicente Fernández's 'Volver Volver' packs every element into one song and shows why mariachi endures.

Start with Vicente Fernández's 'Volver Volver' (1972) — every element in one song, four minutes long. José Alfredo Jiménez's 'El Rey' shows how the ranchera lyric maps onto the mariachi ensemble. For a pure instrumental showpiece, Mariachi Vargas de Tecalitlán's 'La Negra' — their signature — captures the 6/8 huapango feel at its cleanest. Late night, tequila within reach, is the correct listening posture.

The etymology 'mariachi from French mariage (wedding)' is a folk theory now discredited; the word probably comes from a local Nahuatl or Spanish colloquialism. UNESCO added mariachi to its Intangible Cultural Heritage list in 2011. The annual Encuentro Internacional del Mariachi in Guadalajara, running since 1994, draws mariachi ensembles from France, Japan, Colombia, and the US. Japan's own mariachi ensemble, Mariachi Samurai Azteca, has performed at Mexican embassy events in Tokyo since 2007.