Anyone who trains in a Japanese martial art dating from before or during Sengoku Jidai (Japan's "Warring States" period) will tell you exactly how utterly pragmatic it is.
I study both German and Japanese swordsmanship (Hyoho Niten Ichi Ryu). The techniques are really quite similar, and any reading of Go Rin No Sho certainly strikes a chord with those who have read the German masters. The main difference is the focus on the bind in the German school, which is not often present in many Japanese ryuha.
One is reminded of the manuscript HS 3227a, written in 1389 and formerly attributed to Hanko Dobringer. It states "there is only one art of the sword", and he's right. The principles are universal, but some of the particulars change due to the tools involved, even within a given art.
I once had the honour of doing a demo of German longsword for an HNIR seminar, and the instructor said "that looks a lot like our advanced stuff". There is much more the same between east and west than is different with regards to practical combat techniques. But depending on one's mindset, one will find either the similarities or the differences more interesting. When learning HNIR, I was able off the start to graft it onto the structure that German longsword had given me to understand the basic idea of a given technique, and learn the finer points later. A kenjutsu practicioner could do the same thing in reverse in learning European longsword, of course.
In my view, a late medieval European knight would not have felt much out of place training in a feudal Japanese dojo (cultural issues notwithstanding), and a hypothetical Samurai who found himself training in a German fechtschule would be familiar with much of the syllabus already from his own training. The bigger problem for both of them would be the alien culture, not the combat techniques.