Shield break jump
The shield break jump, or SBJ, is a simple aerial attack available to Ness and Yoshi in Super Smash Bros. It makes use of their double jump cancel, and the orientation of the N64 controller. The SBJ is an extremely quick attack that if used properly against a shielded opponent (repeatedly), will break their shield. The attack works by quickly jumping, then immediately jumping again, and then using Ness' neutral aerial or down aerial attack. With Yoshi, it will only work with neutral air. The nature of the DJC stops their momentum, and they will land immediately after performing it, without lag, allowing for another SBJ.
Performing the SBJ
To perform the SBJ, a player can simply quickly jump twice, then attack. It can be performed easily by tapping the right C button on the N64 controller, then sliding to the 'A' button, hitting the down C button on the way there. If done correctly, it will appear as if an aerial attack has been unleashed without leaving the ground.
Another way a player can perform the SBJ is to double tap a C button to jump, and immediately press the 'R' shoulder button with the index or middle finger to attack.