Michael Ellefson wrote:
BTW, shouldn't a Seidokan guy have a thicker skin?"
I'm sorry, but I don't see the connection. Am I missing something?
I'll be sure to let you know if we have a PK or PPK fail.
There are three types of failures that are common in Japanese sword. One is taking a set during a botched cut. That's just a bent sword and usually can be repaired. This is actually the "intended" failure mode of these blades when properly heat treated. Another is poor construction of the tsuka resulting in a tsuka failure. On looseness or rattle the sword should be repaired and not used again. Total tsuka failure can result in a projectile blade or the blade rotating back into the swordsman, usually tearing up their hands pretty bad.
Blade shattering due to suboptimal heat treat is in general vastly more dangerous. Fatigue stresses build up over time and the "perfectly solid" sword can suddenly shatter resulting in a catastrophic failure even in a "good" cut. The failure of this type usually involves the now broken piece flying in one of three directions. Most common is straight down if the fragment gets tied up with the target. But sometimes they fly forward with great speed, especially if they break at the point of target contact (suboptimal heat treat -- usually overheating resulting in grain growth combined with thin cross section). On other failures when they shatter inside the contact point (usually related again to suboptimal heat treat and thinner cross sections) they flip back at the swordsman, again with considerable velocity. And it will still have that long, sharp edge.
Odds of these failure are low. But the repurcussions of a failure like the latter are rather significant. Kinda like playing russian roulette with a gun with 100 chambers and only one bullet.
Best of luck.