It's an unusual technique that disables all the opponent's attack to intercept and strike at exactly the same place where Siegfried has been targeted in the blink of an eye. As stated by Niijima, it can not be explained logically. It's able to counter weapons and deal enormous damage.
Siegfried charges towards the attacking opponent, then exposes himself to allow his foe to strike his vitals, only to strike back in the same areas he was attacked in the blink of an eye with heavy blows. Judging by the name, Siegfried strains his inner muscles to push back the blade without being cut, and even managing to break the blade in the process.