What role does a shield play?

[Jasper]

Originally posted by Jader:
Don't you think it's because katana is a two handed sword...

That would be a No-Dachi, IIRC. A Katana is easily useable in one hand (better reach, from horseback, etc.); it's two handed use is a matter of style.

Actually they used shields called "tate" as protection from arrows or spears. And sometimes they used a "sode" (the piece of armor worn on the shoulder) which samurai could untie and use like buckler for deflecting arrows.

I'm having a hard time finding a reference to a "Tate" outside of Anime, no doubt because it also seems to be a common English name.

Perhaps you could provide a link or source? I'd dearly love to see a picture!