Comments by "" (@neutronalchemist3241) on "My New Real Samurai Armour from Iron Mountain Armory - Review" video.
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There had been variations, with the katana made in wartime that thended to be less sharp and more resistant, but in general japanese swords are more brittle and prone to breakage than a European sword of the same size, in exchange of them being sharper. Katanas are not really made for parrying, they are made to bring a single deadly slash to an uncovered part of the enemy's body, or to die in the attempt.
Samurai doesn't use shields cause, for most of their history, they had been mounted archers that used the tachi / katana as their secondary weapon, and mounted archers (see Parts, Huns, Mongols...) doesn't use shields (you can't use it while throwing, it doesn't cover the horse...).
Other than the samurai, the foot soldiers were mostly conscript peasants, and those were rarely armed with more than a spear in Europe too.
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