Zoro originally fought using just 2 swords until Kuina died:
So why did Zoro suddenly changed his style?
Well, because his promise:
Zoro is still fulfilling the dream for both, he changed his style because Kuina is still with him, he carries her sword as a symbol that both are still after the same dream.
Wow, this is epic, Kuina has always been with Zoro.
So why did Zoro suddenly changed his style?
Well, because his promise:
Zoro is still fulfilling the dream for both, he changed his style because Kuina is still with him, he carries her sword as a symbol that both are still after the same dream.
Wow, this is epic, Kuina has always been with Zoro.