Obtaining the Biggoron’s Sword is quite a lengthly quest, but it’s worth getting it. The sword is verypotent, dealing twice the amount of damage the Master Sword deals. The downside to Biggoron’s Sword is that it is a two-handed blade, thus you cannot equip your shield with it.
Start as adult Link. Firstly, you need to get the ‘Pocket Egg’ from the Cucco woman in Kakariko Village. To quickly hatch the egg, play the sun song twice in order to make one day pass. From there, head to the house in Kakariko village in which Talon is sleeping:
Once inside the house, target Talon and use the newly hatched Cucco on him. He’ll wake up in a Frenzy. Note that in order to pass this point, you need to complete the Epona Quest. If you have done so, Talon will be pleased that his ranch is safe again, and head back to it.
Once Talon is back at Lon Lon Ranch go back to the Cucco woman. She will allow you to keep your newly hatched Cucco. After that, play the Minuet of Forest song on your Ocarina to teleport to the Lost Woods. Head through the Sacred Forest Meadow as usual. The moment you get to the Lost Woods, run into the left passage where you will find an old guy sleeping by a tree stump.
Wake him up with your Cucco and he will ask you to take a Mushroom to the old hag in Kakariko village’s potion shop. However, the Mushroom spoils quickly, so you have to get to the old hag fast. When you accept the quest a timer will appear, so escape the Lost Woods as quickly as possible and head for the old hag’s potion shop. You have 3 minutes to complete your errand, which is actually plenty of time.
Once you enter the shop in the screenshot above, go out the back entrance beside the counter and run to the red house just outside. Inside the red house is the old hag who will give you an ‘Odd Potion.’ You are to bring this potion back to the old guy in the Lost Woods, so head back there.
… only to discover a girl who says the guy isn’t there anymore. She implies he has gotten lost, and has been turned into a Stalfos. If you present the odd potion to her she will demand it, in return giving you a ‘Poacher’s Saw.’ From here, you need to head to Gerudo Valley. Ride into the valley on Epona, and use her to leap over the broken bridge. Accross the bridge is a construction worker. Speak to him and present the Poacher’s Saw. In exchange for the saw, he will give you the Broken Biggoron’s Sword.
Now you need to pay Biggoron a visit. Play the Bolero of Fire to warp to Death Mountain, and head up to the Death Mountain Trail. He will offer to repair your broken sword, but his eyes are irritated as the result of a volcanic eruption. He will give you a prescription for Eye drops. You are to visit King Zora at Zora’s Domain in order to obtain the Eye Drops for Biggoron.
Once you’re done trecking all the way to King Zora, he will tell you he does not have any eye drops, but he does possess the ingredients to make them. He’ll give you the Eyeball Frog, which you need to take to the doctor at the lake laboratory. However, the Eyeball Frog must remain fresh when you get to the lab. Once again, your errand will be timed – you will have 3 minutes to deliver the Eyeball Frog. Note that if you play an Ocarina Song to teleport somewhere, the frong will automatically expire and you’ll have to go back to King Zora.
Note: For this part, if you have planted a magic bean in the sprout beside Dodongo’s Cavern, this part will be easier.Show the Eyeball Frog to the crazy doctor inside, and after a bit of conversation he’ll turn it into the eye drops needed to cure Biggoron. However, the doctor is unable to add any preservatives to the eye drops, so you have to get them to Biggoron quickly before expiration. You have four minutes to get back to Biggoron. Ride to Kakariko and head up the Death Mountain to Biggoron. If you get the Eye Drops to Biggoron on time, he’ll take your broken sword and start fixing it.
The only catch to this is that you have to wait a few days before the final product is finished. If you are dying to get
the sword play the Sun Song numerous times to make a couple of days pass by. Once Biggoron has finished his work, he will
present you with the Biggoron Sword!