ISG stands for Infinite Sword Glitch and is what many would consider to be one of the most important glitches in OoT. When ISG is active Link's sword (or any other item that can be used to crouch stab such as hammer or deku stick) will be constantly in a "swinging" state with an active hitbox. It is visually apparent when ISG is active since Link's sword will glow white as it does when it is mid-swing. You can also tell ISG is active even if your sword is put away due to the effect the glitch has on the camera's behavior. The camera will no longer track Link properly and you will be able to run nearly off screen. The screen will also often be constantly letterboxed as if you were targeting. Another very important effect is Link's inability to fall off ledges while ISG is active. This leads to the ability to Hover in the presence of a damage source.
ISG deals damage on every frame equal to the amount dealt by the crouch stab used to activate it. This can be variable however, due to Power Crouch Stabbing. If your goal is to deal the most damage quickly, you'll want to jumpslash to store the damage value before getting ISG.
How to Perform ISG Edit
There are several ways to activate ISG, but they are all based on the same concept: ISG happens when you interrupt a crouch stab on the correct Frame with an action such as talking, reading, or lifting. When the stab is interrupted on this frame, the game is unable to deactivate the sword's hitbox, thus leaving it on indefinitely. Regardless of what action is used to interrupt the stab, the timing for the interruption will be the same for all means of getting ISG. Since the glitch is frame-perfect, you will need to develop the ability to time it consistently.
ISG is most often gotten by reading a sign, talking to an NPC, lifting a bomb, or talking to navi as the interruption for the stab. Note that most of these are simply an A-button press at the right time while holding R for shield and after pressing B to stab. Talking to navi is different, however and requires you to press C-up. If navi is already prompting you to talk to her, this is no issue. But if you are targeting an enemy, you won't be able to crouch stab while targeting. So in order to get ISG off of enemy navi-text, you will need to stab, quickly press target then press C-up. This targets the enemy while the stab is occurring, giving you the option to talk to navi when the time is right.
ISG is deactivated several ways. Dying or crossing a loading zone will stop the effect. Using shield if you are not holding target ends the glitch, as does swinging the sword (or whatever item has the effect), climbing anything that requires Link to jump off the ground, and taking any damage that moves Link's position. If you are running while taking damage, the damage source does not move you and therefore ISG will remain active.
In the above video you can see ISG being performed and utilized, as well as several effects being shown off. Please take note of the controller input display to determine how best to mimic what is shown. The following list of time stamps shows notable moments.
- At 0:10 ISG is performed by reading the text on the grave.
- At 0:15 the white glow signalling success is clearly visible.
- At 0:19 the sword is sheathed and ISG remains active
- 0:20-0:27 odd camera effect is shown. Camera has trouble tracking Link correctly.
- 0:30-0:40 Link climbs a ledge and is unable to fall off.
- 0:41 Link backflips in order to draw the sword without deactivating ISG since a backflip draw does not make the sword slash.
- 0:49 The sword is swapped for the hammer and ISG remains active. The damage dealt is still that of a sword power crouch stab.
- 0:58 Shows off active hitbox by cutting bushes just by putting the sword near them.
- 1:09 Shows rapid damage-dealing quality of ISG by constantly hitting the rock.
- 1:17 ISG is deactivated by swinging the sword
- 1:30 After getting ISG from the grave text again, we deactivate it this time by shielding.
- 1:38 After getting ISG from the grave text again, we show that ISG is not deactivated by shielding if target is held at the same time.
- 1:53 ISG is acquired by stabbing, targeting an enemy, and interrupting the stab with Navi's description of the enemy (C-up) We can then kill the enemy just by walking into it.
- 2:40 ISG is acquired by placing a bomb at Link's feet, and interrupting a stab with lifting the bomb.
- 3:20 ISG is deactivated by standing still next to a damage source so that the damage pushes Link.
- 3:45 we show that ISG is not deactivated by damage if Link is already moving when he is hit.
- 4:00 ISG is deactivated by crossing a loading zone.