Well, the most famous style using both the katana
and the wakizashi
at once, was that founded by Japan's most iconic ronin
, Miyamoto Musashi. It was originally called nito ryu
("two-sword school"... how daringly original
), but was later renamed niten ryu
being the named Musashi used to sign most of what he wrote). As far as I am aware, that style is extinct (I hear Musashi is known to have had a few students, but I don't think any track of them was kept).
That's about all I know on the matter. I think the regulars of this forum should be able to give you some better information.