We now have detailed images of these ultimate suji bachi kabuto including rare interior views thanks to several forum members. For the first time that I know of the 120 wavy plate doubled suji interior is now available for everyone to see as well. The images and discussion that has taken place goes a long way towards being able to grasp the complexity of these remarkable helmets.
120 plate kabuto.
120 plate kabuto with 60 wavy interior plates visible due to the plates being doubled up, this kabuto also has a "byo", a small washer seen on the inner front part of the helmet which overlaps the two plates on either side of the central plate.
120 plate kabuto with 60 interior wavy plates shown next to a computer drawing by Jeff Mayhew showing the construction method.
All, Beautiful images and drawings of the 120 outside / 60 inside helmet bowls. Many thanks. There are however two points I think worth making. One of the problems of helmet bowls with a large number of plates is that each plate becomes very narrow towards the tehen and the holes drilled for the rivets become disproportionately large as the plate gets narrower. If all the rivets are positioned on the same horizontal line, the helmet would be more holes than plates at that level and be weak. By waving the plates, rivets on alternate plates are staggered up and down to avoid this. My second point is that I have often wondered why these helmet bowls with so many plates were made at all - apart from demonstrating the supreme skill of their makers. The penny (substitute: cent, franc, mark, yen etc has finally dropped. Towards the tehen the effective thickness of the bowl to a cut from a sword or the penetration of an arrow becomes the sum of the thickness of the overlapping plates plus the height of the suji, which are so close together in this region as to present an almost solid surface. Combine that with the fact that the plates twist as they approach the tehen and are almost on edge at the tehen and you get a tremendous thickness of metal there without having to use thick metal plates in their construction. Ian B
Will do....lets talk about levels of manufacturing difficulty between the styles...Aymeric you start...heehee
Mark, one noticeable difference between the two styles of 120 plate internal construction that I can see with the few images available is that the wavy plate design with 60 visible interior plates appears much cleaner or less cluttered than the 120 plate interior.
Since it was not necessary to use the wavy plate method why use it, it looks like a lot more work, was it all about producing a kabuto that looked as nice on the inside as the outside, just more of a vanity / craftsmanship thing, taking it to the last possible level.
I think we should be careful before asserting a particular juggment at the top of our 21 th century. Must first at take care to look more closely at the technic used on each kabuto (Neo / Saotome) an dunderstand more precisely the scope. These kabuto are not from same school and probably not quite same time. The only thing they have in common is that they are 120 suji kabuto.
For me they are primarily the best proof of the reflexion and great Masters extreme expertise in the development of technical way of making of Japanese kabuto.