I understand the Crane stances and know there are more than one. I am referring to the single leg crane stance. I also know that stances are only used briefly. But I am curious, does this stance have any bunkai applications? Or is it only useful against dodging a kick or preparing to kick?
Great question. This is one of those stances that I believe can be more static in nature. I think this stance, as Kokoro points out, is a great example of a lying-on-the-floor technique without actually having to lie on the floor. There are 3 kinds of crane stances, that I'me aware of: 1) the left foot is placed behind the right knee and the left foot's shin is perpendicular to the floor 2) the left foot is placed next to right knee and the left foot's shin is perpendicular to the floor 3) the left foot is placed next to right knee and the left foot's shin is ANGLED (sticks out to the left) to the floor in method 1), the application can represent a bind, hook, or pull toward you, of opponet's knee/shin while standing or lying down. in method 2), the there are a couple of applications: 2a) it is a on-the-floor position where you are mounted; your knee up represents keeping the distance open between you and opponent. 2b) it is a chamber of sorts to a jumping front snap kick (some call this a crane kick, which was a question that was asked about this a day or two ago) - and Shadam mentions this again in this question 2c) it is a check or block of a kick or weapon, as Liondancer mentions. in method 3), the application represents that your opponent is kicked to the inside of the knee: either to disable or to sweep.
I use it for evading/stepping away from an attack, against a front leg sweep, you shift your weight to the other leg and pull up the front leg, blocking/checking a kick, striking with the knee, breaking down a foundation on the downward motion, hooking/trapping opponents leg on the upward motion especially if you hook your own foot around your leg you are standing on, sweeping,.... just a few applications that come to mind off the tippy top of my head. So you see it is by no means just a defensive stance and can be quite offensive too.
In your search for a literal identification of the crane stance, or any physical move for that matter concerning any martial arts is problematic. Although fighting techniques can be identified clearly and others obscure. Instead, try looking at it for its most elementary purpose. That is to say not what can I do with it , but rather what it actually is. By definition any stance is a method of travel to get form place to place, and to enhance your defense and offensive techniques. But not limited to only that. The possibilities then become whatever you discover! As a mater of fact, during any give day the amount of times you use a single leg stance would surprise you. I hope this helps.
What you call Crane stance with a single leg in contact with the ground actually has many applications besides kicking. BTW: As I understand it, doesn't bunkai mean application? The single leg stance is also a mean to focus power from one rooted leg to your punch. The mechanics for a kick from the crane stance can also be used in a punch. It is actually the same. The force you exert from that single leg against the ground or your root-ness is transmitted through your body to the fist or even a block. Think about a situation where you are rapidly transferring your weight from one leg to the other such as when you are backpedaling or moving quickly and see an opening to strike. The power for that strike can still be generated by that one single leg in that instance when it is properly rooted. So rather than planting both legs first and then strike, you can do so with just that single leg that is already in place.