Ok, it’s what I thought. Firstly, the crane stance would be used to avoid a sweep. Think of it as a standing sweep, not one of those sweeps where the sweeper drops down low. Rather from an upright position he tries to hook behind your ankle with his right foot (against your left) and pull your foot out from under you. So you rise into crane stance. It’s quick and brief and fleeting, you don’t hold the foot up because that would leave you vulnerable. But you lift to avoid his hooking sweep and then put it back down once his foot has passed under you. But simultaneously the low block could be reinterpreted as a jamming move to his upper thigh, meant to disrupt his sweep. You’d could even do that as a two-handed move to make it stronger. So what the upper block would be, I’m not sure off the top of my head, but I just interpreted a useful function of most of that posture from that form.