This blade has been honed nearly to obliteration and would be a candidate for a regrind to 1/2 but can obviously still be used. It does not shave anymore as once intended, it's now a lot stiffer. If you want to find similar blades look for stiff 1/2 blades. The fact that the bevel almost touches the stabiliser and the geometry of the head show the use.

The chamfered sides of the head identify it as a 'Schorkopf' in german. Sorry, don't know the matching english name. You can see examples in [1] and [2] where [3] shows a head geometry more similar to what's left of yours.


[1] http://up.picr.de/3276782.jpg
[2] Art.Nr. 1001
[3] http://up.picr.de/3091777.jpg