Originally posted by Howard Clark
Two bars of the same material of the same section will always have the same stiffness IF they also have the same microstructure.
Usually, blades with bo-hi have a thicker mune and shinogi-ji, which plays into what you were saying about changing the section geometry.
I can make tachikaze with nearly any sword, as can most of the guys I know who cut well. It IS louder and slightly different in blades with bo-hi, because the turbulence sets up a different resonance than a "normal" blade without the bo-hi.
The bottom like here is, if you like them, fine, if you don't like them, that's fine too. The fact that a blade has or has not bo-hi indicates nothing else, it wither has or has not bo-hi. There COULD BE something more, like camoflaging ware, or not.
I don't like cutting them, and charge a lot for doing it because I don't like it, and I am not happy unless I do a good job, which takes a great deal of time. So mostly I don't. Most of the serious cutters I know do not use swords with bo-hi, because they tend to bend easier than thos without. (because all other things are not equal)