Kokiri Sword
Used by Kid Link, the Kokiri Sword lies within a chest located in Kokiri Forest's Forest Training Center. Head into a crawl space near the Know It All Brothers house to enter a small maze. Avoid the large boulder rolling around inside of the maze, heading east to approach the chest containing the Kokiri Sword.
Master Sword
The Master Sword resides in the Temple of Time and is stuck in the center of a pedestal. To release it, collect all three Spiritual Stones--Kokiri's Emerald, Goron's Ruby and Zora's Sapphire--and place them on the pedestal near the Door of Time. Play the Song of Time to open the chamber where the Master Sword awaits.
Giant's Knife
Adult Link obtains the Giant's Knife in Goron City after paying 200 rupees, allowing Medigoron to forge it. Accessing Medigoron's shop requires Kid Link to bomb a few cracked walls on the second floor that close off the entrance of the tunnel leading there. The Giant's Knife breaks after extensive use, rendering it weaker than the other swords in the game.
Biggoron's Sword, Part 1
Link must undergo a sequence of trades to obtain the strongest sword in the game, Biggoron's Sword. Starting in Kakariko Village, talk to a woman to get a Pocket Egg. Hatch the egg into a Pocket Cucco, and use the Cucco in front of a Kakariko villager named Talon to wake him. Return the Cucco to the first woman to get a rare Cucco named Cojiro. Take Cojiro to a man named Grog, who's sleeping near the Lost Woods entrance. Take the Odd Mushroom from Grog, and go to the Kakariko Village Potions Shop, where an old woman resides. Link will have three minutes to get to the shop, without warping, or the mushroom will disappear. Give the old woman the mushroom to receive an Odd Potion.
Biggoron's Sword, Part 2
Trade Grog the Odd Potion for a Poacher's Saw, and give this to Mutoh of Gerudo Valley for the Broken Goron's Sword. Take the Broken Sword to Biggoron, who resides at the top of Death Mountain. Take his Prescription to King Zora in Zora's Domain to get the Eyeball Frog. Within three minutes, take the frog to the Lakeside Laboratory, where the scientist there will turn it into Eye Drops. Take the eyedrops back to Biggoron within four minutes, without warping, to get the Claim Check. Wait three days, and give Biggoron the Claim Check to finally receive Biggoron's Sword.