Pictured are two Nihonto. As you can see, the polish on the mune at the kissaki has a "dull" or frosted finish that runs about 5 1/2 cm on the mune from the tip of the kissaki towards the mune-machi. What, if any, purpose does this have? The only thing I've heard is that this type of polish is for Tameshigiri to give a visual reference to be at the proper distance to the target.
Any other ideas?