Most Katanas would fail against hard blows to cinder blocks - especially centuries ago. Not a Swamp Rat.
The Japanese were building with cinder blocks centuries ago? I had no idea. Was that one of the technologies introduced by space aliens?
Or wait! Maybe the Mongols invaded Japan in order to sell the shogun cinder blocks. It was all a plot to break those nasty katanas. Yes, that makes more sense.
Knife Guy, you're a wealth of information.
