If that back edge IS actually sharp then the ball is still in the air. 
If not, then I suspect that what were are actually seeing is a variant of the 'Sosun pata' with a wide almost 'Tegha-esq' blade profile. 
Probobly 19thC, and 'villlager' grade. 
A nice thing, worth cleaning up I'd say.
		 
		
		
		
			
		
		
		
		
		
		
		
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