In shoten no jutsu (running to heaven) the martial artist is using ukemi to run up walls and other vertical surfaces.
Initially the training begin with a slight incline and over time, along with ukemi skill, increases in angle, until arriving at a complete 90 degree angle.
Similarly, the running approach to the vertical surface begins far away, with plenty of time to build up momentum. More and more the approach length is shortened, until the point where it can just *happen*.
How high should one be able to run up a wall or vertical surface.
8-12 feet would be a good starting point to aim for.
In practice, at the top, one lets go and uses ukemi to land and roll safely, so shoten training should begin after a good foundation of ukemi has been developed.
The key in training is to be able to fluidly shift from the running part to the vertical lifting part without smashing into the wall or losing momentum.
Taihenjutsu is used for this.
Naturally shoten no jutsu is a way to escape, but if one can run up a wall, or fence, once can easily run up a person, or over objects such as cars.