I guess that explains how ryoma could use it in the anime vs yukimura.
I guess this also proves that Irie is on a level that if he understands how the technique is done , he can replicate.
this begs the question, are all people affected by this technique able to see the ice shards?
if so, Frozen world is like a mind genjutsu/eye technique type, it makes you freeze mobility wise temporarily (not arm swings), even if the explanation is it hits your blind spots.
it would explain why everyone victim to this technique always says " what? I couldnt move"
in reality if someone in real time tennis aims at your blind spot you can move as you see/anticipate the ball coming. so this move of course isnt realistic.
this would also explain why yukimura told sanada in pot1, that he would have lost. because yuki mura has eye powers and he saw through atobe's
frozen world while it was happening to sanada, when only the user of the technique or the victim of it should only perceive the ice shards.
or yukimura recognizes that atobe can temporarily freeze an opponent's movements, similar to his own eye powers.