Congrats, interesting Sulu blade and I especially like the hilt, too! 
 
I'd posit that this is a twistcore blade (i.e. torsion pattern welding) that has been flattened out to cover the actual steel core and only a little bit of the surface got grinded away for the finishing of the blade. 
 
Could you please provide more close-ups, also from the distal part of the blade, Xas? 
 
Regards, 
Kai
		 
		
		
		
		
		
		
		
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