A eukaryotically conserved histone deacetylase complex which deacetylates histones preferentially in promoter regions. Composed of a catalytic histone deacetylase subunit, a chromodomain protein, a SIN3 family co-repressor, and a WD repeat protein (Clr6p, Alp13p, Pst2p, and Prw1p respectively in Schizosaccharomyces; Rpd3p, Sin3p, Ume1p, Rco1p and Eaf3 in Saccharomyces; homologs thereof in other species).