there's a little cheat, of course. It's like the time you haven't gone to the drug store and you're with your girlfriend...just this once..
..wait, never mind.
But, with the saw, the first time, just the tip.....
....of the teeth.
jeez.
at any rate, just filing the last little bits until there's nothing rounded, and you're good to go.
I do this with disposable japanese saws with a diamond file. I know I've read a million times that they can't be resharpened. They're impulse hardened - but diamonds file them just fine. then there's "you'll file off the hard part and the saw won't hold its edge".
OK ....I'm using a 240 z saw that's been refiled and boy was it an improvement over the dull saw and boy have i not noticed it to have a problem holding the edge. But like this saw, I'm not going to look for something to drop the gullet.
This thread also inspired me to just go out and get the z blades off of the japanese auction site. 24 of them for $120.
Apparently the 265mm version is a replacement for the 240 because it's the one everywhere now. I'll dump all but about 5 of them in groups on ebay and share the wealth with some other folks who may not like the idea of $25 with shipping for a $5 replacement blade.