Chris, am I right in assuming you are using the fukuro shinai for free sparring as part of the TNBBC? If that's the case I can certainly understand a desire to go with seam-as-mune! OTOH, I think seam-as-edge adds a nice, slight sense of edge-fear to keep practice alive when doing kata-geiko. I don't know if that's why Shinkage-ryu and others do it that way, but I do know I try to avoid getting hit with that seam!
