Unsupported headstand, interesting variation

This is the nirlamba sirsasana, on the back of the hands. I like this simply because it is tougher than the other unsupported variations and I believe could be secret preparation behind totally leaving your hands in the headstand. I tried it too, though, as usual, for just a fraction of a second.
What u need for this pose:

• A great unsupported headstand, with a light center. At the basic level, with elbows bent
• Then, the hands straight, palms down version, again with a great center. 
• Then this one. 

It is a very light pose and u should be prepared for several falls, usually to the side, when you start trying it, till subtle muscles in the shoulders learn to cope with this new, more demanding variation. Like all things that need to be light, it requires more intense focus and more strength. 

Only really strong things can be really light:)