Board Thread:Versus Debates/@comment-3523655-20200802172018/@comment-39350828-20200803160444

David Kibasennin wrote: Also, Shiki Fujin is a forbidden technique. If we're gonna speculate, I wouldn't compare it to chidori, which has been used and abused as a technique, I'd compare it to other forbidden techniques.

off the top of my head:
 * Chiyo's bringing-back-to-life technique was performed without her being cloned.
 * Edo Tensei has been performed by only one person, non-cloned.
 * Guy going into the 8th gate does so as a single person, doesn't use clones.

Just by doing that, we see Hiruzen using Shiki Fujin with cloning is an exception to a general rule. I don't think the reason they don't use edo tensei with clones is because they can't. I think it's because there's never really been a perceived need for that. With the 8th gates the reason is probably because the damage from having it active would make the clones dispel whereas with the shiki fujin their souls only start getting eaten after the technique is completed. Chiyo didn't know shadow clone jutsu so even if it was possible she wouldn't have known. It's possible that she couldn't have done it even with shadow clones but if so it's not necessarily because she lacks some arcane knowledge that hiruzen had about how to combine shadow clones and a life-sacrificing technique. It could be because her technique simply requires a user's full undivided life force so unlike the shiki fujin, it would be incompatible with shadow clone jutsu.