Oh? Considering that it could knock out nine Bijuu simultaneously, you're going to tell me that Hashirama is going to tank Rinbo Hengoku which's power will be focused solely on Hashirama instead of nine Bijuu enemies this time? Not only would he most likely be either killed or at least be left unconscious after getting hit by an attacking such as that, he'll need time to heal from such a powerful attack. Time that he won't get against Madara. He'll sense the Chakra build up in Madara's eye, however he doesn't know what Rinbo Hengoku is nor what does it do. He'll never expect a force to suddenly knock him out.
lol, and why on Earth would Madara do that? If he did that he'd go flying, giving him enough time to create and land on Mokuton. It isn't the repelling effect itself which causes the damage, it's landing on the ground which won't happen if he's hit with so much force that he goes flying up. Also, Deva Path didn't use a Bunta/village size Shinra Tensei against Kakashi so why would Madara use such force against Hashirama? They don't go over the top unless they have to which is why Hashirama only pulled out Shinsuusenju when he had to, which is why Deva Path used a massive Shinra Tensei when he had to, which is why Madara used a Bijuu size Rinbo Hengoku when he had to. They only use such massive scaled techniques when it's necessary. Once he's realized Madara's about to launch attack, Hashirama then launches his. Simple fighting common sense; to act before your opponent does. At least then only his Mokuton would be destroyed and Hashirama would be left untouched.
