The Vals is tango danced to Waltz music played with tango instrumentation. It can be danced in either open or close embrace. It is danced in a smooth and flowing movement, but no staccato. The Vals music is played and danced in 3/4 rhythm or beat (1-2-3) rather than the standard 4/4, with an accent on the first beat. When dancing the Vals, there is lots of rotation. Popular steps include the Calesita (or Carousel) and Molinete.
Although the rhythm of the Argentine Tango and the Viennese Waltz are essentially the same, a big difference between the two is in the speed. Viennese waltz is slower allowing for a step on each beat. Tango Vals is faster so usually a step is only made on the first beat in each bar. You normally dance it with a step on the ONE beat of the ONE-two-three beats of each measure. This lets you dance slowly and do some of the more elaborate tango figures. You can also do a bit of waltz-like up-and-down motion. Some of the most beautiful, happy, and romantic tango music was written as a tango vals.
Tango dancers dance the Vals in a rather relaxed, smooth flowing dancing style in contrast to Viennese Waltz where the dancers often take 3 steps per measure and turn almost constantly. Experienced dancers alternate the smooth one-beat-per-measure walk with some double time steps stepping on one- two- or (rarely) all three beats in a measure. Vals dancing is characterized by absence of pauses.
Here is a good example of the Vals: