[Ragabash]

Yup, that's the names for the weapons. And also going with the whole two-handedness thing, the only one-handed weapon mentioned before, the wakizashi, was basically the main thing, that separated a soldier from a samurai. If a person had a wakizashi, that meant he's from nobility, or a samurai, otherwise, without the wakizashi, a person was a mere soldier. It was the only weapon, that a samurai could carry into a household of another nobility.

So that leaves all the other weapons to the cannon fodder, hence - no shields.

And if we'd take into account all the other one-handed weapons, as I can think of this little sickle, the kama, that was used in Japan as a weapon, if I'm not mistaken, those were a reaction to the ban of swords for the common men. Farmers and other not so noble and cool people had to defend themselves, so they adapted. However, these adaptation, to my knowledge, were never widely used in armies and major battles.

Oh, and I agree with the 48h, got carried away : )