Board Thread:Theories and Speculation/@comment-27821571-20160915183730/@comment-3279282-20160917212411

My personal theory (and I really don't like sharing it) is that the Juin is Magnet Release and it seals the sand body so that it doesn't break down. This is based on the fact that Narutos MR Rasengan only has the Juin applied (there's no sand in the manga), so if the Juin is the only new thing, it's the only possible reason why there's MR in the technique's name.

But that's just my headcanon.