But i have also read it said that knights were utterly useless off their horses? or is that the difference of jousting armors vs combat armors?
I still think all things being equal, a samurai would have more ease of movement, there is nothing i have seen in a armor suit or someone wearing one, where it would lead me to believe in any way shape or form they could move change directions efficiently. Yes you would get used to it using it frequently but it is still not natural, toss in the heat inside one of them while being active...
Katanas were better cutters than european swords (in general) the curve blade having a better cutting property, and harder sharper edge in general, and you could still stop them cutting you by stepping into the cut, the final 1/3 of the blade where a sword is moving the fastest has the most cut and progressively less as you move inside that, i have to imagine that knights had similar techniques to stop sword strikes, but if samurai armor is effective at dealing with katana strikes, glancing yari stabs, i doubt it can or will struggle against much of what a knight can bring.
At any rate i think a far more interesting match is a 2 unarmored warriors with their weapons of choice, let technique and style decide the day.
And between those 2 i think unarmored it is a pretty even match up. maybe even ad to the european would be larger in general have more reach in general.
But armored i think the samurai has it on mobility. If it is horse combat few archers were better than samurai archers, yumi were powerful long range bows i am reasonably sure would puncture any armor it can hit. On foot i do not think it is even close though. Like a huge lumbering giant off to fight the agile little fighter.
Which incidently is why some give an edge to the rapier due to its speed.
I guess it is all about speed vs raw tank or power and where your faith lies.
That would most definitely be true with armour for the joust, but field plate was designed with foot combat in mind. The nature of medieval warfare meant that being unhorsed was a distinct possibility. Then you get into earlier periods where maille was king, and the flexibility of maille doesn't inhibit movement much at all.
As for Japanese armours, ones like the Do-maru provide a similar range of movement to that of western harness. The O-yoroi however was a different beast altogether. It developed from a time where battles were decided by duels between warriors on horseback, shooting at each other with their yumi. The way it's worn makes it sit on the thighs when mounted, but on foot, the entire 60 odd pounds of armour hangs from the shoulders, making it exhausting to wear on foot for extended periods of time. The design of it is also much like a metal box, which inhibits the sort of movements needed to fence with a katana, hence the yari being their preferred weapon after the bow. The O-yoroi was eventually replaced by armours like the Do-maru because tactics shifted toward infantry blocks and the O-yoroi became a liability to its wearer.
As an aside, the Tatami style armours are very similar in construction to Turkish armours.
As for cutting....basically, when fighting in armour cutting is ineffective. Steels don't readily cut each other (and hardened and Lacquered leather, which was used extensively in Japanese armour, is surprisingly durable) which was the part of the reason European longswords and fencing evolved the way they did, becoming stiffer with more wickedly pointed tips, for thrusting into gaps and bursting maille rings. It is also the reason weapons like the warhammer and the poleaxe were popular weapons, you could injure or kill the man inside without ruining your expensive sword (and for the religious, a handy way to get around bible verses against killing people. See, you're not actually spilling blood when bludgeoning someone......) and overall more efficient when fighting in armour.
On bows....again, it really depends on the period, but it would be safe to say that decent European armour made after 1350 would be reasonably proof against bows. English accounts of the Battle of Poitiers in 1356 make note that French armour stopped English arrows to the point where it was called 'invulnerable', and the Battle of Agincourt was much more of a royal French fuck up than the triumph of the longbow (considering the English had exhausted their arrows on the first of 3 waves). I haven't been able to find any definite numbers on the draw weight of the yumi, but if up to 90lbs is true, that's roughly equivalent to the longbow, so if the Samurai is up against plate and mail or full plate, he's going to have to be an extraordinary shot to land an arrow in one of the few places that are vulnerable to them.
Looking at armours of earlier periods, the Samurai definitely has a range advantage, but it's not an auto win and I don't think he'd be as quick as you'd think. If he's on wearing an O-yoroi (which would be likely if he's on horseback), his armour is close to being twice as heavy as a maille clad knight, so he probably wouldn't be able to just dart away. I haven't found firm numbers on the weight of the Do-maru but from what I've read it looks like they weren't significantly lighter than contemporary European armours, and due to the social status of those wearing them at that time would mean they're not likely to be on horseback to start of with. Due to the cost involved in getting one, the O-yoroi was also a status symbol, and it took some time for the Do-maru to make its way up to the higher social strata.
As for penetrating armour, there are many variables to take into account, such as range, angle of the shot and what the arrowhead is made of (if it isn't iron or steel, I'm pretty sure that the effort of punching through maille, if it does at all, would deform the head to such a state that it wont get through the padded garment underneath). Crusading knights in the Holy Lands during 11th and 12th centuries were often described as looking like pincushions, with all the arrows sticking out of them and still fighting strong. Plus, maille clad knights would invariably be using a shield as well, so a Samurai will have to place his shot very carefully. All in all knight in maille has a good chance of survival, so that leaves us with single combat. Against a Samurai in a Do-maru or something similar, the battle comes down to training and skill. In an O-yoroi, there's still a decent amount of training and skill involved but if the knight can get inside the Samurai's yari, then I think its advantage knight, he's simply far more mobile.