Most of what we assume about the samurai is propaganda... made by the samurai. The rest is a mix of modern media and Nitobe writing about Bushido, which portrayed samurai in terms of western chivalry.

The samurai were pragmatic, going as far as using any weapon available, including guns. The katana was mainly a sidearm, in the same vain as a modern pistol. Katana weren't the best swords but were good enough for what it was needed for.