This is interesting as Iwata sensei advises us to use shorter light swords with small tsuba so you can draw fast against guys with big swords with large tsuba. Note he is 'old school' MJER and often refers to the Tosa area, which is where he lives...
Looking at Oe Masaji's sword, I would say it looks light as well, so I am wondering if it is the original Eishin only guys who favoured the larger heavy swords? All the guys I met at Kochi city MJER dojo also used light swords, so 'in theory' Yamauchi ha should be similar as Oe sensei taught the founder of this branch... Even the shimomura ha sensei from Kochi dojo uses a light short blade, so I would also be interested in origins for the prevalence of longer swords in MSR I see here in the UK.
Tim Hamilton
Why are you reading this instead of being out training? No excuses accepted...