The technology in Naruto is a complete mess.
There is electricity, fine electronics and printing are in wide use, but the reciprocating engine or even basic wheel hasn't been invented. Wooden cabins, mud huts or caves are used for housing, except for the poorest war-torn village which can afford itself concrete skyscrapers.
Shoes covering the toes do not exist!
But at least the lack of gunpowder is intentional.
Interviewer: Do you have any rules about what is definitely not allowed to be drawn in the "Naruto" world?
Kishimoto: Firstly, projectile weapons such as guns aren't allowed. (The one exception
is Inari's bowgun.) Guns aren't suited to ninja. Gunpowder is used in the anime,
though I don't think it should be there. And, vehicles such as aeroplanes are
not allowed. I try to restrain technology that can be used for war… For
example, if missiles were in it, it'd be the end. (laughs)
Obviously, that was before Kishimoto has thought of strategic tailed beasts and intercontinental ballistic eyes.
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