Board Thread:Speculation House/@comment-1860621-20140815015907/@comment-9090085-20140822092056

Here's my understanding of her semblance: it passively absorbs energy when she gets hit and stores that energy in her hair; when she gets angry, her semblance enters it's active state, releasing some that stored energy(angrier = more energy released).

Or, to use the fighting game analogy Monty used: Yang has a Super Gauge that fills up as she gets hit; she is then able to spend some of that meter on supped-up attacks(EX moves), or a lot of her meter on Ultra-powerful attacks(Super moves).

That Samson reference may be more apt then it might appear - Yang's semblance stores energy in her hair, so if someone were to cut off her hair, she wouldn't have anywhere to store the energy from her opponent's blows, effectively disabling her semblance. Furthermore, despite having Aura and a semblance that may-or-may not reduce damage taken, her hair has consistently been cut or pulled out in fights, suggesting that it's not properly protected by those two defenses I just mentioned.

In other words, Yangs hair is her weakness - it's the key to her power, and is vulnerable to attack.