Heavily improvised, taking any form the interpreter wishes.
On One / On Two
Salsa on One, or briefly, "On One", is characterized as so because it starts on the first count of the 8-beat rhythm. Alternatively, if the first step (with the left foot) occurs on count 2 or 6, it is called "On Two".
Some consider dancing "On Two" to work more closely to the clave rhythm, the most basic rhythm of salsa music, as the steps start on the first tick of a 2-3 son clave. However, dancing "On One" hits just as many beats in the clave and hits the first tick if the music is using a 3-2 style son clave.
In short, it's a matter of personal preference which counting to use, and most people prefer the counting of the style they were taught first when they began dancing salsa.
Colombian Style Salsa is the style danced in South and Central America. In the Colombian style basic-step, partners dance side-to-side, mirror each other's movements, and often times is danced with very limited or no turns at all. Additionally, the break is on the three and the "spare beat" is always used for a tap or other embellishment.
Colombian Style can be danced not only to Salsa music, but also to Cumbia music, which is frequently played in Latin nightclubs. In advanced Colombian style, danced for example in Cali, the upper body is kept still, poised, and relaxed while executing endless intricacies in the feet.
This style is especially appropriate on packed nightclub dance floors where space is limited. Most of the steps danced during the Merengue, another Latin dance which is popular in Salsa clubs, have been carried over from Colombian style Salsa.
It is said that Colombian salsa evolved during the big band swing era, when swing dance steps were danced to Cumbia music. Cumbia was traditionally danced in folkloric ensembles without holding one's partner.
The original Salsa style, as considered by most, which has been developing in Cuba since the 1950's. Cuban-style salsa can be danced either "on one" or "a contratiempo" ---the latter is often referred to as "on two". An essential element is the "cuba step" (also known as Guapea), where the leader does a backward basic on 1-2-3 and a forward basic on 5-6-7. The follower does the same, thereby mirroring the leader's movement. Another characteristic of this style is that in many patterns the leader and follower circle around each other.
The cross body lead is an essential step in this style too and is referred to as Dile que no. This move becomes essential in the more complex derivative of Cuban Casino leading to the many moves of Rueda, or wheel dance.
Los Angeles Style
Developed in recent years (some say between 1999 and 2002), this is a style of salsa much influenced by Hollywood and by the swing & mambo dances, thus being the most flashy style, which is considered "more show than dance" by many.
The two essential elements of this dance are the forward/backward basic as described above, and the cross-body lead. In this pattern, the leader steps forward on 1, steps to the right on 2-3 while turning 90 degrees counter-clockwise (facing to the left). The follower then steps forward on 5-6, and turns on 7-8, while the leader makes another 90 degrees counter-clockwise. After these 8 counts, the leader and follower have exchanged their positions.
New York style
New York style emphasises efficiency of movement, elegance, and body isolations. By focusing on control, timing, and precision of technique, dancers aim for smooth execution of tightly woven complex patterns.
In New York City, this style is danced strictly On 2, although dancers around the world often integrate elements and repertoire from New York into their dancing On 1.
On 2, timing emphasises the conga drum's tumbao pattern, and encourages the dancer to listen to percussive elements of the music. Advocate of New York Style consider this to more accurately reflect the Afro-Caribbean ancestry of the music.
In a social setting, New York style is danced more compactly than LA style. The etiquette of New York style is strict about remaining in the
"slot" and avoiding travelling. Also, the style tends to place a greater emphasis on performing "shines" where dancers separate and dance solo
for a time.
Puerto Rican style
This style can be danced as "On One" or "On Two". If danced as "On Two", it is always danced on count 2, and not on count 6 as in Ladies-style NY. There is a Salsa Congress in Puerto Rico where salsa groups all around the world attend and perform.
In the 1950s Salsa Rueda (Rueda de Casino) was developed in Havana, Cuba. Pairs of dancers form a circle with dance moves called out by one person. Many of the moves involve rapidly swapping partners.
There two main types of Rueda de Casino: (1) Cuban-style "Rueda de Cuba" and (2) Miami-style "Rueda de Miami" which is more formal with rules based on a mix, hybridization of Rueda de Cuba and Salsa Los Angeles-style.
Normally, Salsa is a partner dance, danced in a handhold. However advanced dancers always include shines, which are basically "show-offs" and involve fancy footwork and body actions, danced in separation. They are supposed to be improvisational breaks, but there are a huge number of "standard" shines. Also, they fit best during the mambo sections of the tune, but they may be danced whenever the dancers feel appropriate. They are a good recovery trick when the connection or beat is lost during a complicated move, or simply to catch the breath.
One possible origin of the name shine is attributed to the period when non-latin tap-dancers would frequent Latin clubs in New York in the 1950's. In tap, when an individual dancer would perform a solo freestyle move, it was considered their "moment to shine". On seeing Salsa dancers perform similar moves the name was transposed and eventually stuck, leading to these moves being called 'shines'. ~ Music of Puerto Rico