Everyone knows katanas are the best weapon in history and they can cut through anything. Also, because they are made out of adamantium everyone knows that they are the fastest and lightest weapons on earth. They should not get caught on scenery and walls because they can easily cut through stone and wood of all types.
Please also add shield breaking ability, to show how katanas are the supreme cutting devastators of the medieval world and can cut through any conceivable material that a shield might be made out of. Unless the shield is also made of adamantium. In that case the katana won't have shield breaking ability, but can still break the shield because although they are both made out of adamantium, the shield is not a katana and therefore cannot withstand the force of a katana.
Also, please change katana damage to piercing damage. This will accurately signify the the devastating armor-cutting qualities of a katana blade. My friend had a katana from Japan and my other friend had a car once and the first friend accidently dropped the katana on the other friends car and then the blade happened to be facing down so when he dropped it fell on the hood of the car and sliced through the hood and the engine and all the way down through the front tire and got stuck in the road. And that was just from dropping it so imagine if it was swung! We were all like OMG WTF and then we ran away.
So from realism this makes total sense, dont' hate!