I disagree with some of this. A katana can be made more curved or less curved. During some periods of sword making in japan katanas tended to be ore curved than others and as such less effective in stabing. All eras katanas could stab though.I have had the good fortune to learn the use of both the Katana and the western longsword from masters who inherited their teachings and the two are almost nothing alike.
That was an extremely interesting test. Very good read.A really interesting link to testing of different weapons in different cultures in history.
Those that think that a katana cant stab, think again. Pleas read.