Let me start off by saying that the Polka is not danced very often at your typical Contradance. To recognize the music, listen for a fast-paced tune with 4 counts to the measure. In the event the band does play a Polka, you probably won't find anyone dancing the basic step. Other Scandinavian dances with a more structured set of steps and turns are more popular.

        The Polka was introduced into the ballrooms of France and England in 1843. The Times of London described it as embracing the "intimacy of the waltz combined with the vivacity of the Irish jig". It's hard to imagine a time when the quick little closing half step was a novelty, yet from it, the dance was named. Polka, from the bohemian word pulka, which means half, refers to the little half step or close-step that is characteristic of this dance. One of the easiest ways to understand the rythm of the Polka is from this children's song:
               "Hippety hop, to the barber shop,
               To buy a stick of candy."

        The four counts of that little "hippety-hop" (step, half-step, step, hold) describe the feel of the basic step. (It is very similar to the Schottische, but the timing is different.)

        It would be nice to describe the Polka position and be done with it, but there is no such animal. In practicing the basic step which follows, you should try it both in the regular dance or waltz position and also side by side, with your arm around your partner's waist, and her hand on your near shoulder.

Basic Step

        The hop is a little preliminary hop, like a grace note in music. The first step is preceded by this hop. It is a question whether to call it an echo of the fourth beat or the promise of the first beat.
        Many people reduce the hop to a slight and quick rise and fall of the weighted foot before starting the first step. Some omit it altogether.
Analysis of the Man's step (Woman's part is mirror image)
A. Stand with weight on R foot, dance forward with    
      Give preliminary hop on R foot and step forward on L foot 1  
      Close the R foot to the L, taking weight on R foot 2  
      Step again on L foot 3  
      Hold, keeping weight on L foot 4 1
B. Repeat all to the other side with    
      Give preliminary hop on L foot and step forward on R foot 1  
      Close the L foot to R, taking weight on L foot 2  
      Step again on R foot 3  
      Hold, keeping weight on R foot 4 2
  Repeat A and B    

        If you want to perfect it, get that little grace note, preliminary hop, down pat. If you want it to correspond to the authentic step of the golden age of the Polka, make that last step a very light leap. Don't make the step any longer, but leave the floor very slightly in taking it.
        Now try going backward as well as forward. Try turning to the left and the right.

There are some interesting variations to the basic step which I will get around to eventually.