For the sake of my own education, I'll bite. It's my understanding that hagire can form from stress during quenching, but also from stress during use (and someone please correct me if I'm mistaken). It makes sense that a showato would be very unlikely to develop a stress crack at quenching since the temperature is lower and the steel is more uniform. However, any hardened steel will fatigue/crack under the right circumstances, so why is it impossible for a showato to develop hagire?
Just asking.
(And I'm not saying this one has. In one of the last pictures it looks like it, but you don't see it any of the other photos, or at least I don't, so I suspect it's an artifact).