Bo Diddley and Chuck Berry, 'Two Great Guitars' (1964)
By the mid-Sixties, Chess Records was ruled by two astounding axmen: Berry and Bo Diddley. It was inevitable that they'd be thrown onto an album together. The product, 1964's Two Great Guitars, isn't as exciting as its premise would portend; the record comprises only four tracks, with two of them being so-so offerings from Berry and Diddley solo. The remaining two cuts, though, are something else entirely. "Chuck's Beat" and "Bo's Beat" are epic jam sessions between the two guitarists, clocking in at 10 and 14 minutes, respectively – at a time when such long songs were highly unusual on rock records. The duo made the extended format work, too, pushing each other to foot-stomping, string-bashing extremes.