The Razor Sword is the first upgrade to the Kokiri Sword in Majora's Mask. To acquire it, Link must have approximately one hundred Rupees, and it cannot be the final day. Then he must go to the Mountain Smithy and pay the man there one hundred Rupees; it takes a day to finish the sword. Unfortunately, the Razor Sword will only be "razored" for one hundred strikes, then it will turn back to normal. One must have the Razor Sword before getting the Gilded Sword.
Soul Calibur II
In Soul Calibur II, the Razor Sword is one of Link's many weapons. The weapon is purchased in the Weapon Master Mode, in the first region of the mode, Regulus. It is the first weapon that can be purchased to be used by Link. It has a higher attack power than the Master Sword, though it lacks the reach of the blade, and Link takes damage when blocking with this weapon.
Razor Sword model from Soulcalibur II