Op sa! is a spontaneous exclamation often used while dancing. There is no exact English translation, but it is something like “whee,” “yippee,” or “ee-haw!”
In July of 1994, Dick Crum introduced this dance at Stockton. Crum’s quote from the Stockton notes: “Opsa is currently one of the most popular dances at Croatian and Serbian dance events in the major cities of the Upper Midwest and the Pennsylvania/Ohio area. Its melody is relatively recent, having been composed and recorded in former Yugoslavia about a decade ago. The origins of the dance per se are obscure – it seems to have arisen here in the United States, possibly around Pittsburgh. On the other hand, its structure has the same 5-measure pattern as the old Serbian Vranjanka. I first saw and learned it at the Tamburitza Extravaganza weekend in Los Angeles, 1993, where tamburica players and fans of tamburica music from all over the United States had gathered, and Opsa was played and danced dozens of times.”
Based on the above information, corroborated by Serbian dance authority Alex Marković in email correspondence, Opsa, is a 5-measure dance, a product of the Serbian-American community. The same recording is popular in Serbia to accompany the Serbian dance Sa, Sa (or plain Sa, sometimes also called Opsa), which has a 3-measure pattern, a variant of the Taproot Dance. I cannot find a YouTube of someone in Serbia dancing a 5-measure Opsa, and Alex Marković says he’s never seen it danced there, either.
Here’s the only YouTube I could find of Opsa being danced in a North American Serbian or Croatian event.
However, there are many YouTubes of recreational folk dancers doing Opsa.
Here’s Paul teaching the dance, starting at the 8:35 mark.
So what’s the connection to Vranjanka? Here’s the recreational folk dance version of Vranjanka.
Clicking this link https://folkdancefootnotes.org/dance/a-real-folk-dance-what-is-it/1st-generation-dances/vranjanka-tesko-sano-duso-belo-lence-serbia-kosovo-n-macedonia/ will give you the whole rundown on Vranjanka, its history, how it was once popular in Serbia, mostly as a dance in 7/8 time, but is no longer a Living dance there. It came to North America over 100 years ago and was kept alive here by the immigrant (and later recreational folk dance) communities. So, the speculation goes, when the new recording of Nenad’s Op sa (at the top of this posting) hit these shores in the 1980’s, someone decided to dust off the 5-measure Vranjanka footwork and adapt it to Op sa‘s lively 2/4 Čoček beat. Quoting Alex Marković “I’d agree with Dick Crum that the 5 measure form (what you call Op Sa) must have been an innovation here in the U.S.; essentially the pattern is Vranjanka, and Serbs in Serbia would think that is what they were seeing, regardless of the “sa” music. Vranjanka is traditionally associated with tunes in 7/8, though, and not 2/4 or 4/4, so there is also that distinction.” What we don’t know is if the innovators in North America knew that in the old country the locals were dancing a 3-measure pattern to the same music.
Forrest Johnson, in the comments to the Society of Folk Dance Historians Enclyclopedia article on Opsa, © 2018 by Ron Houston, writes: “I first saw this dance several years ago at a Tammies post-performance dinner-dance in Milwaukee – they led it. I picked it up there and taught it to folkdancers in the Milwaukee area and at the Door County Folk Festival. Serbian and Croatian bands have played Opsa since that time in the Milwaukee area for the dancing public. What is interesting in Milwaukee is that when Croatians hear this melody they do the dance as you described, sort of a Lesnoto with a back step. When Serbs here hear the melody they do the dance Sa Sa which is really like Makedonikos or what I call a “running Čoček“. We have happily been doing both versions for many years in Milwaukee.”
So apparently some Serbian and possibly Croatian groups in North America hear Opsa music and dance a 3-measure dance to it, just like their counterparts in Serbia. For instance:
For more on the 3-measure Serbian dance with many names, most with the word sa somewhere, click: https://folkdancefootnotes.org/dance/a-real-folk-dance-what-is-it/about/sa-sa-sa-op-sa-niski-sasa-serbia/