Ah, tango.

It is an intricate, delicate dance of seduction that confounds American two-steppers, except for the ones it captivates.

The heat rising from the Railroad Stage at the American Folk Festival early Saturday afternoon was matched only by sun beating down on those enthralled by tango — the music and the dance.

Hector Del Curto’s Eternal Tango Quartet and dancers Ivan Terrazas and Sara Grdan served up a sumptuous portion of the Argentine tradition that bears no resemblance to the American version with dancers cheek to cheek.

Like his grandfather and great-grandfather before him, Del Curto plays the bandoneon. The bandoneon first appeared in December 1850 in a German music shop owned by Henreich Band, according to information on web sites about the history of tango. A cross between a concertina and an accordion, the instrument quickly became the soul of tango when it reached Buenos Aires at the end of the 19th century.

Del Curto formed the group, based in New York City, in 2003 to keep a family tradition alive. His wife, cellist Jisoo Ok, pianist Gustavo Casenave and violinist Nick Danielson joined him at the festival along with Argentine native Terrazas and Croatian Grdan. All are classically trained but somewhere along the line were enchanted by tango.

The site lines at the Railroad Stage and the limited area allocated to the dancers made it nearly impossible for more than a quarter of the audience to observe them. It was one of the few times a big screen projection of the stage would have been an asset.

The musicians, however, played perfectly. Their music wrapped festival goers in a blanket of the somehow soothing, yet alluring, sound of seduction.

Ah, tango.

The quartet will perform at 8:45 p.m. Saturday at the Dance Tent and at 5:15 p.m. Sunday at the Penobscot Stage.