Slash Extension is a trick that increases the size of the hitbox of Link's sword attacks. It works with Swords and Deku Sticks. To perform the trick, pause during the triple slash animation then pause repeatedly without allowing a frame to advance. This causes the hitbox to increase until the upper limit is reached. Then, unpause and your sword attack's hitbox will be larger than normal. The address which tracks the size of your hitbox is a byte at 8040088D on the US version. It counts up by 2 each time you pause and has a limit of 128.
There are 5 types of attacks you can extend:
-Jumpslash
-Horizontal Triple Slash
-Vertical Triple Slash
-Right Triple Slash
-Forward Lunge Triple Slash