Night Club Two Step was originally created to replace the "Slow Dance" (the hug and sway dance). The original timing of the "Side Basic" pattern was: 1, &, 2; 3, &, 4 (½, ½, whole; ½, ½, whole). The foot pattern was: "Rock Backward, In-place, Side Step; Rock Backward, In-place, Side Step". This allowed it to be danced to very slow music in a compact space.
Night Club Two Step eventually became a Country Western Dance. The timing of the "Side Basic" pattern evolved to: "Slow, Quick, Quick; Slow, Quick, Quick". The foot pattern evolved to: "Side Step, Rock Backward, In-place; Side Step, Rock Backward, In-place". This change necessitated faster music, but it still remained a rather compact dance.
Night Club Two Step has very little footwork, if any at all (heels, toes, balls, rise, fall, etc.). There is a very logical reason for this. Country Western dancers wear cowboy boots when they dance. Cowboy boots are heavy, bulky and stiff. The Country Western dancer's footwork is basically a flat shuffle type of step. This creates a flat feeling in the dance and the "Rock Step" gives the dance a forward and back sort of choppy feeling.
Over time, it crossed over into Ballroom dancing. Night Club Two Step was then "Ballroomized". Fundamentally, technique and footwork were added to the dance. The footwork is a modified Waltz rise and fall. The "Side Step" became a powerful, gliding side movement. As a result, the "Rock Backward" step no longer worked because of the sideways power. The "Rock Backward" step had to be changed to a "Side-Crossing Step" in order to control the power. This changed the feeling of the dance from a forward and back sort of choppy dance to a powerful flowing side-to-side dance. The dance is no longer compact. It has become quite wide and expansive. Since the dance had changed so dramatically in feeling, it had to be renamed. "Ballroom Two Step" was then born.
The patterns are similar between the two dances but they are danced quite differently. The dancing I am referring to is the footwork and CBM (contra body movement). The standard Waltz footwork is "Heel, Ball, Ball-Flat". Waltz has a "heel" step only on the 1st step forward. Most of Ballroom Two Step's movement is side-to-side. There is only one "heel" step and it is on the forward step of the "Left Turn" pattern. The footwork for Ballroom Two Step is "Ball-Flat, Ball, Ball-Flat".
The 1st power side step (Slow) is Ball-Flat. The 2nd step (Quick) is a very "side-crossing" step on a "Ball" only. The third step (Quick) is an in-place step "Ball-Flat". The power of the 1st side step combined with the 2nd "Ball" only side-crossing step, creates a lifting action and then a falling action on the 3rd "Ball-Flat" step. This is not a typical rise and fall action. It is more like an up and down "Lilting" movement. Think of yourself on a child's swing with someone pushing you. You are powered forward, you swing up, you hesitate and you swing down. This is the feeling of Ballroom Two Step. The side step powers the movement then you glide to rise on the 2nd step and then finally fall on the 3rd step. All of the 2nd steps in Ballroom Two Step are "Ball" only. This creates the "Lilting" action on every element (measure of music). It feels like power to the side then gliding up and down. This is very different than the Night Club Two Step's flat walking motion.
The side-crossing steps are not "Rock" steps. A "Rock" step moves backward and creates air between your thighs. A side-crossing step moves sideways to such an extent that the upper thighs touch (No air). The action of the thighs touching is called "TWEEZING". CBM is used to lead the ladies crossing steps either in front of or behind her.
Although Ballroom Two Step can be danced to almost any 4/4 time song, just like any other dance, it has its own unique music, A real Ballroom Two Step song will have a "CLICK" on the 3rd beat (2nd step). Sometimes the "CLICK" may be on every other 3rd beat. A classic Ballroom Two Step song is "Lady In Red".
Night Club Two Step has a flat, back and forth, walking feeling when danced. This has great appeal to "Pattern Dancers" (dancers that basically walk through patterns instead of dancing). Dancing is what happens between the steps. Some ballroom dance instructors still teach Night Club Two Step simply because it's easier to teach. I teach what (in my opinion) feels the best, not what is easiest to teach. Ballroom Two Step is a powerful, sweeping, gliding, side-to-side dance with a little lilt. Take the time to learn to dance it. It has a great feeling.