Is it worth getting?

[mas4t0]

It kind of looks like it's been "repaired".

 

Crack propagation is caused by the immense stress concentration at the crack tip.

 

 

This causes the crack to propagate through the material as shown below. 

 

 

The way to "repair" a crack without patching it or inserting material is known as stop-drilling. The end of the crack is drilled to reduce the stress concentration and prevent further propagation. 

 

 

The kirikomi doesn't look natural to me. While it obviously hasn't been drilled, it looks like someone has eased the end of it.

 

This is the correct thing to do from a fracture mechanics perspective, but I'm not sure if I'm seeing things correctly.

 

Does anyone know of this being done on blades where it's worthwhile? I've never heard of or seen it before on nihonto so I'm quite curious.

[Shugyosha]

Hi Mark, your post put me in mind of another thread from a while back about using laser micro welding to repair flaws in swords. I’ve no idea if that has been done here but There’s something about Lewis’s post with the shadow running up from the hakobori that made me think of it too. Piers’ post a little way down is telling.