I just finished reading a good "popularization" of the Spartan's stand at Thermopolae called "The Fire Gate" that, I *think*, holds a clue.
The Greek heavy infantry (Hoplites) fought as well-disciplined teams, using heavy shields and inter-locked armor in fixed formations. (Or rather, their main front-line formations worked this way - to the rear were various archers, sling-throwers, guys with javelins, what have you.) The front-line guys used heavyish one-handed spears as their prime weapon, wielded overhand in a "repeated downward stabbing" motion. At a walk, they'd advance and just chew through damn near anything, shrugging off missile attacks with the armor and shields. Their backup weapon was a short "heavy chopping" type sword closely related to a modern Nepalese Khukuri...Bill Martino of Himalayan Imports can sell you a 21" (overall) Sirupati that'll handle very similarly to a Greek Kopis. Like the spear, it was a "heavy smash" weapon that didn't need a lot of finess, or FOOTWORK.
Key point: if a guy got so tired he shrugged off his armor or helmet, that was considered unwise but not dishonorable or what we'd call a "court-martial offense". But to drop your SHIELD meant losing your citizenship! Why? Because your shield wasn't there to protect you, it was there to protect the guy to your left. What does this imply?
NO FOOTWORK!
The Romans adopted the Greek tactics, with a few twists. Shields got bigger yet, and the "interlocked shields" concept even more clearly defined, to where they could stand against cavalry. Primary weapon switched to a short "heavy stabbing" sword - straight thrusts could be performed through the shield wall without breaking it.
These concepts of closely-spaced individual soldiers forming a "solid wall" and attacking as a unit continued in European thinking, with some exceptions of course (Scots!). But in general, the Japanese sword systems absolutely, positively *required* "side-stepping" and other fancy footwork that went against the grain of European tactics.
The Japanese tended to fight as mobs of highly skilled individuals. Assuming they could avoid being outflanked, I'd be willing to bet a Roman Legion or a Hoplite Phalanx could have walked right up to double their number of Bushido and handed 'em their tail ends on a platter.
But one on one, in a duel? Whole 'nuther story
- Mr. Gladiator or whatever just found hisself in biiiig trouble.
Now, later European "dueling schools" in the Italian and Spanish traditions are a whole different critter again than a Legionaire. I'll leave the "rapier versus katana" debate to others.
What I'm saying is that the Japanese "cut and dodge" system of *battlefield* skills developed as an entirely different path than the European systems at their Greek and Roman roots. The Rapier-type and similar European systems were NOT battlefield-bred, they were "personal defense for noblemen in peacetime". The Japanese also went down that path, esp. by the Edo period, but the "battlefield roots" of the dueling schools were much closer to the surface.
Jim