Group R6-1 is similar to Groups Q5-1 and Q6-1, except that the higher pyramid structure is on the south side of the courtyard. The basal platform of the complex is built of dolomitic limestone blocks. A circular altar rests at the base of the pyramid and a small structure occupies the centre of the courtyard, an unusual feature that is not often found in the Maya lowlands although other examples have been identified at Tikal and Uaxactun. This group has been dated to the Late Classic.