"Throughout the lastest generation, no other force on the planet has been feared more than Hashiramas Wood. His Wood was of such great quality that many shinobi feared it. If you ask the female shinobi, almost all of them will tell you legends of his once great wood. As a result, many seeked to obtain wood with such unheardof qualities as that which belonged to Hashirama. Through trial and error, Orochimara was able to duplicate the wood himself, but due to being caught redhanded in his various "experiments" with his newly found wood, he became scared that rumors would float around about him playing and polishing it, so he ran and eventually got away. Of the other hand, Kabuto was able to get his hands on the 1st's Genuine Wood, and despite being a male shinobi, he gave it to Madara Uchiha to make him much better with the females in theory. To be honest, Kabutos theory was correct, as even Mei was surprised at Madaras wood, so surprised in fact that she had to pass up the chance at inspecting it carefully, out of fear that it was too much to handle. But neither-the-less, of all people, Tsunades jaw dropped when she saw her grandfathers Wood being put to good use. Lady Tsunade was so jealous that Madara had his hands on her grandfathers wood, that she fought him for it, and he went right along with it. Long story short, Madara "ran up in her" and laid the "wooden pipes" on her. Tsunade fought well, and despite being know for her strength, even she was no match for Madaras wood, as he split her in half with its mightiness. He had Mei lying face down on her stomach, motionless and satisfied"
ANOTHER REFERENCE
Tsunade didn't have enough "Brain" power to realize that she couldn't beat Madara. So she thought she'd knock some sense into him and decided to give him some "Brain". After inspecting Madaras "Wood Grain", he beat here senseless and "Split" her in half.... literally..."