How did they expect the Z Sword to defeat Buu?

[Polyphase Avatron]

Before the truth about the sword was revealed, everyone seemed to think it was just a heavy sword. They tested its cutting power with a boulder and then a block of Katchin. But even if the sword had cut through the Katchin, how would that have helped against Buu? A sword is completely useless against him - you could slice him up as many times as you wanted and he'd just regenerate.

[LoganForkHands73]

Shin and Kibito were convinced that the sword would automatically give its user the ultimate power. They were blinded by their own misplaced belief in the legendary Z-Sword and thought it would solve all their problems, even though it clearly wouldn't work against a regenerating being such as Majin Buu. They probably expected it to shoot laser beams or something, but it just turned out to be an ordinary albeit ridiculously heavy sword (though of course, Elder Kai being inside it was the real magic they needed). Gohan even says it must have been a really overexaggerated legend.

Besides, the scene of Gohan breaking it might be the funniest scene in the whole franchise.

[Koitsukai]

I always thought they would use it like Trunks vs Freeza. Slice him into little pieces and blast him away forever. Easy to slice but impossible to obliterate, unless the guy wielding the sword had the power to do that.

The Z sword did make Gohan much stronger due to training with such a heavy tool, impossible to remove from that mountain, so I guess they were thinking that a dude strong enough to swing that sword like it aint no thang, would also be enough to overpower Buu and deal the finishing blow.

Keep in mind they were fighting Fat Buu at the time, and Gohan might've gotten strong enough in his SS2 form to actually defeat him. It wouldn't have been crazy, SS2 Vegeta got mad and surpassed SS3 in BoG.

[Desassina]

It would be magical and cut through Boo like Trunks's Spirit Sword cut through Zamasu and made him a wall paper.

[Polyphase Avatron]

I always thought they would use it like Trunks vs Freeza. Slice him into little pieces and blast him away forever. Easy to slice but impossible to obliterate, unless the guy wielding the sword had the power to do that.

The Z sword did make Gohan much stronger due to training with such a heavy tool, impossible to remove from that mountain, so I guess they were thinking that a dude strong enough to swing that sword like it aint no thang, would also be enough to overpower Buu and deal the finishing blow.

Keep in mind they were fighting Fat Buu at the time, and Gohan might've gotten strong enough in his SS2 form to actually defeat him. It wouldn't have been crazy, SS2 Vegeta got mad and surpassed SS3 in BoG.

But anyone who could beat Buu that way wouldn't need a sword to do it. And they clearly believed that the sword itself had some kind of power that would let Gohan win.

[theherodjl]

I always thought they would use it like Trunks vs Freeza. Slice him into little pieces and blast him away forever. Easy to slice but impossible to obliterate, unless the guy wielding the sword had the power to do that.

The Z sword did make Gohan much stronger due to training with such a heavy tool, impossible to remove from that mountain, so I guess they were thinking that a dude strong enough to swing that sword like it aint no thang, would also be enough to overpower Buu and deal the finishing blow.

Keep in mind they were fighting Fat Buu at the time, and Gohan might've gotten strong enough in his SS2 form to actually defeat him. It wouldn't have been crazy, SS2 Vegeta got mad and surpassed SS3 in BoG.

I really doubt that swinging a heavy sword around for several hours increased Gohan's strength by more than 10%, if even by simply 10%. Any belief that Gohan's power had rose by a significant amount was probably just wishful thinking on Shin's part and him perpetuating the myth that the Z Sword itself was ever anything more than just a sword.
If anything, the Z Sword training merely conditioned Gohan to fight at the level he once held against Cell, returning him to peak strength rather than increasing it.