The Muramasa is a blue-bladed weapon with a very fast attack speed (the highest speed of all swords pre-hardmode). The Muramasa can be swung continuously by holding down the attack key. It also emits a faint amount of blue light upon being swung, much like a Blue Torch, the Hammush, and the Mushroom Spear when being swung. This sword cannot be crafted and can only be found inside the Dungeon. It emits a humming sound when swung.
- The Muramasa was the fastest sword in the game, but since the 1.2 update, there are new swords introduced that are faster than the Muramasa, such as the Cutlass. This makes it the 4th fastest sword in the game.
- In Pre-hardmode, it is one of the best swords next to the Blade of Grass, Fiery Greatsword, and Night's Edge.
- Due to its high speed, it can be a useful weapon even in Hardmode, but it is advised to use hardmode swords such as the Breaker Blade or Cobalt Sword instead once they are available.
- The Muramasa is highly effective against enemies in the Dungeon because of the large number of enemies in the dungeon it can easily kill because of its fast speed.
- Blue Moon has the same blue particle effect.
- With Violent Accessories (Feral Claws, Power Glove, Mechanical Glove, Fire Gauntlet and Celestial Stone) and Hallowed Armor equipped (with mask), its speed is incredibly fast.
- Muramasa is a reference to the legendary Japanese swordsmith, who made blades that were said to be cursed, inspiring bloodlust within those who wield them.
- Damage increased slightly from 18 to 19.
- Use time decreased from 20 to 18.
- Knockback increased from 1 to 2.5.
- Reduced damage from 22 to 18.
- Reduced knockback from 3 to 1.
- Became an ingredient in Night's Edge.
- Added to the game.