There really isn't a style of swordsmanship that uses it all the time, but there are situational uses for the reverse grip that are historically documented. Fiore dei Liberi holds the sword in a reverse grip with the purpose of wanting to throw the sword like a javelin which [Skallagrim has demonstrated before on his channel.][1] [![enter image description here][2]][2] Historical Japanese and Chinese swordsmanship occasionally seems to show it used for certain situations: [![enter image description here][3]][3] [![enter image description here][4]][4] And in iaido/iaijutsu it is occasionally done, but primarily as a method of returning the sword comfortably and also during very specific situations when the sword can **only** be retrieved in a reverse grip: [![enter image description here][5]][5] The reverse grip is especially important if you want to comfortably draw and sheathe an especially long sword since it will allow a tighter angle to be made when drawing/sheathing without putting too much strain on your wrist. [![enter image description here][6]][6] It also is occasionally done on particularly short "swords" [like butterfly swords from Wing Chun][7] and are a way to use your forearms as a blocking tool kind of like how a tonfa would work or [as a method to use your swords at extremely close ranges where you would be throwing elbow strikes.][8] [![enter image description here][9]][9] Keep in mind with all the examples given though; they are situational moves designed to supplement holding the sword the normal way and not something that is done all the time like seen in fiction-land. :P [1]: https://www.youtube.com/watch?v=QYVIsMQPKzY [2]: https://i.sstatic.net/sxrMc.jpg [3]: https://i.sstatic.net/UahAx.jpg [4]: https://i.sstatic.net/uUQHz.jpg [5]: https://i.sstatic.net/CYWzP.jpg [6]: https://i.sstatic.net/DFc4k.jpg [7]: https://www.youtube.com/watch?v=FaLlwBb38FQ [8]: https://www.youtube.com/watch?v=4BkOvhwDKDs [9]: https://www.shopwingchun.com/wp-content/uploads/screen-capture221.jpg