Samurai shoots knight's horse down, rides right up to the knight and stabs him in the face.

gg

just to show some of the katana's potential, it can do decent damage on platemail.

Not only that, but it cut a huge block of ice. Gotta get some Ice Armor.

If that folding chair was made of folded steel.

It doesn't made sense for an object that is harder to break when hitting something softer, unless it's a shitty design, but folded steel isn't a shitty design.

samurai are trained on their childhood they win

Watch deadlious warrior

Lume's video is crappy,the claymore was nearly blind-edged,and deadliest warrior has shown only the damage(it doesnt mean who would win)

Also,in my experience with katanas,and oriental weapons,an katana can be spinned to become einther an defense or an attack weapon.
They have extremely cutting power,although it has been decreasing since nowadays,in the Samurais age,they could even cut an tree(no joke).In my opinion,it is the best sword ever made.
the shield would come useless against an katana,it's stabbing power was even more huge.
Samurais had an incredible good aim,as they were trained since 3-4 yo.
The samurai bow was made for war,and can reach very far distance.

That battle would be ended,even b4 it starts.
Samurai shoots knight in the head :Samurai wins!

If you have ever swung any sort of blade, you'd know how rigid a katana is compared to a longsword. A katana would NEVER be effective against plate armor with an underlayer of chainmail. Knights wore armor designed to stop long ranged and close ranged weapons. By long range weapons, I do not mean the yumi as it is totally uneffective against armor designed to absorb the piercing force of a 2 pound longbow bolt(fyi, average asian arrows weigh ~50 grams). On horseback, a french knight would have a crossbow(sharpshooting), and an english knight would wield a longbow(raining death). A samurai would have a yumi(raining urine). Nevermind how hard it would be for the samurai/knight to even aim the long range weapons on horseback. A knight's longbow bolt would go all the way through a samurai, while a samurai's yumi arrow has a high chance on deflecting off the surface. On the chance that it manages to pierce the armor, it wouldn't do much more due to the amount of energy absorbed. Same thing would happen if the knight's horse, seeing as they wore thicker armor then knights. Again something else on horseback: ability to couch a lance. Something samurai's could not do due to lack of proper footholds. A katana may be the weapon with the highest cutting power, but it is awfully rigid and it would leave the samurai vunlerable if fighting a shielded foe.

Long story short, knight wins. Samurai wouldn't stand a chance.