Ochos with cha cha cha -- it is a '1-2-3, 1' rhythm, as in 'step-2-3, step'. The 2 tiny extra steps are embellishments that the lady can add in as the man leads a back or forward ocho.
Early tango was known as tango criollo, or simply tango. Today, there are many tango dance styles, including Argentine Tango, Uruguayan Tango, Ballroom tango (American and International styles), Finnish tango and vintage tangos. What many consider to be the authentic tango is that closest to that originally danced in Argentina and Uruguay, though other types of tango have developed into mature dances in their own right.