Board Thread:Theories and Speculation/@comment-30355627-20170128224827/@comment-30426414-20170129234053

Ravenlot 27 wrote: Lorenzo VonMT wrote: Well minato was caught off guard because his kunai broke when he charged obito. His kunai breaking was obvious, since TSBs are a way stronger than a simple kunai. The only thing which could catch him off guard back then was Obito's TTJ transformation (fully-controlled one).

Actually at that point, they haven't fully figured out the nature of the truth seeking balls. Otherwise minato wouldn't have charged him with a kunai.