Opus

Opus is a Slovak record label founded on January 1, 1971, in Bratislava, as the successor to the Supraphon Slovakia branch office. The label was established to handle recordings by Slovak artists or productions with Slovak participation across all genres, and also released licensed material from major international record companies. It operated under state ownership through the socialist period, was privatized in 1991, and has passed through several ownership structures since — including Sony Music / Bonton (Slovakia), Forza Music, and, from 2019, Warner Music Czech Republic s.r.o. The label's registered address was Mlynské nivy 73, Bratislava. Its Label Code is LC 3530 / LC 03530.

Opus pressings from the state-era period follow catalog number schemes that allow for reasonably precise dating and format identification. Mono releases carried numbers beginning with 90, stereo releases with 91, and a 93 prefix appears on some later issues, possibly indicating digital recording. Most vinyl pressed between approximately 1967 and 1992 includes a three-digit manufacturing date code on the side A label, with the first two digits indicating the year and the third indicating the half-year of manufacture. Retail price code suffixes were sometimes appended to catalog numbers on cover art but are not considered part of the official catalog number. First pressings from the early 1970s occasionally omit the date code in favor of side duration times.

Collectors seek out Opus pressings primarily for their documentation of Slovak popular, folk, and classical music during the socialist period, including material that had limited distribution outside Czechoslovakia. The label also issued several notable compilation and reissue series, among them Slovenské Legendárne Albumy, Komplet Originálnych Albumov, and the Opus 100 series. Because represses were typically identical to original pressings aside from stamper codes and manufacturing date markings, careful label and matrix inspection is necessary to identify first pressings. The relative scarcity of original state-era copies outside the region adds to their collectibility.