Many tales and quests bring in the concept of three: three heirs, three suitors, three tasks. Throughout the eukaryotic kingdom, three structural maintenance of chromosomes (SMC) complexes — cohesin, condensin and SMC5–SMC6 — are crucial for chromosome reorganization events and cell viability. Each of these complexes consists of SMC heterodimers and additional non-SMC subunits, and their structures resemble a ring that embraces DNA. Cohesin and condensin are required for the establishment of physical links between sister chromatids and for chromatin compaction, respectively, but the role of SMC5–SMC6 in sustaining chromosome life is less clear. Like its 'sister complexes', the binding of SMC5–SMC6 to chromosomes is integral for its function, and this complex plays a part in chromosome segregation and repair. Interestingly, sister chromatid linkages are known to accumulate in smc6 mutants during the replication of damaged templates, but the mechanism underlying this, and the type of DNA interactions influenced by SMC5–SMC6, are not known.