I have been dancing Casino for almost 5 years now and both during my travels (from watching Cubans dance in Cuba and watching Cuban immigrants dance in various cities across the world) and from watching various youtube videos I couldn't help but notice that a large number of Cubans dance casino on 3. Now, before I get crucified for generalizing, I know that there's a huge number of Cubans who dance a tiempo (on 1) and there is also also a number who don't differentiate between 1-2-3/5-6-7 and just dance 1-2-3/1-2-3, which means there's also a pretty big portion of dancers who dance a tiempo (without caring if it's on 1 or on 5). This makes sense to me. What doesn't make sense to me is how this on 3 thing came about. Is there any reason for this trend? Is there a historical precedent for this development? Is there something in the music that lends it to this kind of dancing? I'm curious if there are people in this forum who have any experience or explanations with regards to this.