I have been recently inundated by emails asking for a katana with a reversed edge.
Some of the correspondence included information on how accurate this sword was in the history of Japan.
Apparently Anime is having the same effect on youngsters as Superman had on my days. Some kids wrapped a towel over their necks and went off the window, firmly believing they would fly.
So I learned about Sakabatou and Zanbatou, and how these swords can cut anything, including steel and gun barrels.
I am really tired of giving the same reply. But I think it is worth the effort so as to avoid any disaster.
A katana with a reversed blade is like having a dish to place the food out of it.
Let me explain better:
1. Enjoy your TV series as what it is. These are not people, they are animated drawings, nothing more. I would call them cartoons, and if they were not so violent as I assume they are, I would put them in the same crazy but healthy category of Daffy Duck, Bugs Bunny, Donald, Goofy and Mickey.

2. Remember that swords, even those double edged, are meant as an extension of the arm's natural movement, that is, to extend for cutting.

3. An edge of a katana is achieved by heating the blade to a very high degree temperature, and then quenching it in water with proper clay masking to obtain the necessary edge hardness. You may read more here.
In other words, the blade will contract (curve) on the softer side, which is the spine or mune.
It is absolutely wrong to want a sharp edge on the softer side for many reasons, among which the sword would never hold an edge. But the most dangerous thing is to swing the cheap blade that is a marketing gadget, and end up cutting yourself in the face or shoulder because your retraction movement with a reversed  ground edge blade will definitely hurt you by accident. Don't fall prey to fiction.

Conclusion: swords and their design are strongly connected for the best performance.
This design-performance ratio has evolved through the centuries, until the best shape came out. Don't fall for a cartoon that is now called anime.

There is one type of partial two edged blade that was used in ancient Japan. It was called the Kogarasu-maru.
If others just care for the money that anime or cartoon (call it as you like) brings to them, I care about your safety.
So please don't ask me for anime swords. For your sake, and mine.
Antonio Cejunior