Board Thread:Questions and Answers/@comment-30953250-20190821085026/@comment-25431873-20190821130538

First, did you watch only the anime version? Because it greatly butchers what actually happens in the fight.

First, the fight is from Accelerator's perspective, so we see what he thinks and what decisions he makes and why. So we learn from his thoughts that while he was trying to kill Touma, and knew that logically there was no way Touma should survive, he genuinely believed Touma would live. His hero worship of Touma is so great that he couldn't see him lose, and wanted Touma to prove it. He desperately wanted Touma to win against him, despairing when he though Touma lost...

OT Volume 20: There was no way the Level 0 boy could have saved himself. And the shock waves created by even one of the dozens of stakes held enough destructive force to smash a human body to pieces. It had to be over. With that victory, Accelerator had lost some form of hope.

...and laughing in joy when he didn't. There is no way Touma should live, no way he should survive the attacks Accelerator throws at him. And yet he does. And is so living proof that fate can be overcome, that the impossible is possible, giving Accelerator hope that maybe, just maybe, he can do that too.

OT Volume 20: “Ha ha ha…” Accelerator laughed weakly. He didn’t understand. That attack was not something the boy should have been able to handle with just his right hand. However, Accelerator clearly laughed. He seemed to be enjoying it. He seemed to enjoy the fact that the theory behind his supposedly undefeatable attack had been overturned. To him it looked like the image of the unstoppable rails of fate being easily overcome.

Incidentally, it proves that Accel did make long range attacks, unlike in the anime. A tsunami of rocks and snow, a deluge of rocks, etc.

Which brings us to the next point: how did Touma survive then? He ran straight into those attacks, and yet none struck true. All were minor wounds. Was it because of "plot"? Not quite.

See, Accelerator even heard about Touma fighting Mikoto, and knows that if you're capable of blocking all attacks that means jack shit if you can't stop the attack in time, which Touma shouldn't as the Railgun moves faster than the speed of sound.

Thus Accelerator forms a theory. One he called Precognition, or Premonition Perception so as to not confuse it with the Precognition esper ability. Accelerator's theory is that Touma is picking up on all kinds of small signs, unconscious tells, that allow him to predict how an attack will go. He allows enemies to use their attacks so he can analyse them, see what tells they have, and then avoid them when he can predict them. And Touma himself doesn't even realise it. He's been in so many fights, against espers, magicians, and street thugs, that he can now slightly predict attacks by the involuntary movements the opponents make and react to it, but he's doing it all subconsciously. He's a combat expert.

All of this is cut from the anime (and I didn't even mention the disrupting use of Imagine Breaker to deal with the black wings that the anime ignored), so Touma just looks like he goes in to punch Accel through the power of determination.

So this is why Touma won.