Although it looks similar to Kosa Dachi (crossed stance) Kake dachi has a totally different intention. Whereas Kosa Dachi is used as a preparation for a turn, Kake Dachi is used as a braking mechanism against a forwards movement.

In the original versions of Bassai/Passai, this stance is used in conjunction with a diagonal movement past the opponent, that could be interpreted as tae sabaki (evasion/body movement), or stepping to add power to the attack.

In that context, the "brake" (the left foot) is applied to prevent over-balancing. If you use the brake in a very high stance, it is innefective, but if you bend your knees a lot, it works perfectly.

Some people suggest that when you see crossed ankles like this, that you are tucking the ankle bones out of harm's way to avoid a sweep or weapon strike. It seems like a strange interpretation as the penalty is such a vulnerable stance, but I can't rule it out completely.

This is a vulnerable position thanks to the crossed legs, which somewhat undermines the stance's readiness for subsequent action. This perhaps suggests that it is part of a commited attack that is is not expected to fail.

Technique

The GKR version of kake dachi is always achieved by shuffling forwards, lead foot moving first., with the braking foot catching up and moving through to act as the brake The lead foot is positioned placing forwards, and the back foot is brought up behind the lead foot to the outside, so that the outer edges of both feet are facing each other and almost touching. By necessity, the heel of the back foot is raised from the floor.

Both knees should be bent, and your hips and shoulders face straight forwards. Almost all of your weight is supported by your front leg, and your centre of gravity is set over your heels. Your back should be straight.

Unfortunately, the GKR version of this stance has been modified so that it's application and effectiveness have been lost. In other styles, the body turns 90 degrees, pivoting on the supporting leg. The braking foot is then much further forwards, and it crosses higher up the other leg, providing a much broader, more stable base.

When executing the traditional form of this stance, the supporting foot is placed at 90 degrees to the front. The braking foot ends up further forwards than the supporting leg.