No hand seals until explain why the change.
/Thread
Yeah, as if Kishi is going to explain that during the war plot. >.>
We MIGHT get an "explanation" in the next data-book though, whenever that will be.
However, this may be an example of retroactive continuity aka retcon, which is the alteration of previously established facts in the continuity of a fictional work. >.>
So in other words, Hiraishin no Jutsu MAY have been done without hand-seals in earlier chapters, but NOW has to perform a hand-seal to activate it.
This page is proof enough:
http://www.mangapanda.com/naruto/639/5Thinking logically now:
Correct me if I am wrong but the only ninjutsu we have seen that does not require hand-seal(s) is rasengan, right? However even rasengan requires the focus/gathering of chakra in order to be performed.
In the case of Hiraishin no Jutsu, have you seen a jutsu that can be activated by a mere thought? Jutsu are performed via chakra, not thought. After all, it would be an equivalent of activating a ninja scroll by simply thinking about it. >.>
Now, it would make sense that Minato may have mastered the technique to the point that he may not need a hand-seal but you cant say that this technique can be performed without at least one hand-seal in the very beginning of its creation. That's highly unlikely.
But then again, here's another thought. If this can be performed without any hand-seals, why does Minato only has 1 kunai in hand? Has there been a page where he's holding two kunai, one in each hand while performing the technique? Mmmm.... >.>
I originally didnt care much about the Hiraishin no Jutsu because there are like (correct me if I am wrong) four "official" users of the technique and I only seen 1 person used it in an offensive matter instead of another shunshin option to use. I am just posting my thoughts on the matter.