Board Thread:Versus Debates/@comment-3523655-20200802172018/@comment-31715856-20200807172447

BloodOfTheArchon wrote: That's speculation. The contract seals only worked on summoned beasts where there is actually a real summoning contract done. Minato can't do that to Edo Tensei otherwise Itachi or somebody else would have done so in the 4th War. Minato also has never shown and isn't said to be able to use the Shiki Fujin Shadow Clone variation like Hiruzen can.

The contract seal... seals, away any contract that allows for a summon. And as Madara said, those summoned by Edo Tensei are bound by such a contract, which Madara himself breaks. Of course, Minato does not actually need to do this, Anko and Hiruzen thought it was obvious Minato was well capable of defeating Orochimaru. The reason this didn't happen in the war is kind of obvious I think: No one knew where Kabuto was because he hid himself behind a barrier that hid his chakra from sensors. Also, we don't know how well known contract seals are, it's fuinjutsu after all so it's already going to be uncommon.