Chum kiu, also known as 'Bridging the Gap' or 'Seeking the Bridge', is the second Wing Chun form taught under Ip Man lineages.
Compared to the the Sil Lum Tao (the first form), the biggest difference is the amount of footwork and kicks.
By watching this video (both a front and side view are demonstrated) you can see the amount of movement used in the form.
The interesting thing about all the footwork in Chum Kiu, especially compared to Tai Chi or Shaolin forms, is that it takes place in a very small space.
You'll notice in the video that this Wing Chun'er uses a very tight space in a crowded living room for the entire form. He simply moved over the sofa.
In other words, this form, the kicks, footwork, attacks, and defensive moves all takes place in the space of your common household couch.
This further demonstrates the close quarters fighting range of this martial art.
If you've even seen or done something like Tai Chi, you know that it's best practiced outdoors or inside a gym with plenty of open space.
Considering that most fighters are long distance fighters, 'closing the gap' so you can fight on the 'inside' is an important skill to develop in Wing Chun.