Castle Walk is a dance

Dance

Dance is an art form that generally refers to movement of the body, usually rhythmic and to music, used as a form of expression, social interaction or presented in a spiritual or performance setting....

 originated and made famous by Vernon and Irene Castle

Vernon and Irene Castle

Vernon and Irene Castle were a husband-and-wife team of ballroom dancers of the early 20th century. They are credited with invigorating the popularity of modern dancing. Vernon Castle was born William Vernon Blyth in Norwich, Norfolk, England...

. The Castle Walk became popular through its introduction into the Tango

Tango (dance)

Tango dance originated in the area of the Rio de la Plata , and spread to the rest of the world soon after....

.

In this dance, the man continually goes forward and the lady backward. In order that the lady may be properly guided about the room, the man's arm encircles her just under her arm, while her left hand rests on the man's right arm. The position of the lady's right arm and the man's left arm is high, with their hands clasped, see the illustration.
The man starts forward with his left foot and the lady backward with her right, simply walking with gliding steps keeping on the toes, one count of the music to each step. This step is continued to the end of the room, where a large circle is begun, which is gradually made smaller and smaller, until it is ended by whirling completely around three times, to three counts of the music and then dip.

The Castle Walk may be varied by describing the figure eight or zig-zag instead of the large circle.

To make the three whirls is rather a difficult matter, as it must be done very rapidly to accomplish
a complete revolution to one beat of the music, but with a little practice it is soon learned.

Troy Kinney

Troy Kinney

Troy Kinney was a notable American artist, etcher, and author.Troy Kinney was most notable for his works portraying dance performers, fanciful subjects, and classically styled nudes. He worked with dance performers, including Ruth St. Denis, Anna Pavlova, and Sophie Pflanz among others...

 describes the Castle Walk as part of One-Step

One-Step

The One-Step was a ballroom dance popular in social dancing at the beginning of the 20th century.Troy Kinney writes that One-Step originated from the Turkey Trot dance, with all mannerisms of the latter removed, so that "of the original 'trot' nothing remains but the basic step".The One-Step...

 as follows:

This is a walking step
of direct advance and retreat, not used to move to the
side. The couple are in closed position, the woman,
therefore, stepping backward as the man steps forward,
and vice versa. The advancing foot is planted in fourth
position, the knee straight, the toe down so that the ball
of the foot strikes the floor first. The walk presents an
appearance of strutting, although the shoulders are held
level, and the body firm; a sharp twist that punctuates
each step is effected by means of pivoting on the supporting
foot. The shoulder and hip movements that originally
characterised the "trot" are no longer practiced.