Super Saiyan 2 (超サイヤ人 ツー) is the direct successor to the first Super Saiyan transformation. It is very similar to the original form in appearance and attainment; however, the power output is far greater, as speed, strength, and energy output all drastically increase. Gohan is the first person to attain the form in the manga, and he uses it while fighting against Cell in the Cell Games. Goku and Vegeta soon follow, with Goku learning it in the Other World and Vegeta learning it on Earth.
Power and Usage
The Super Saiyan 2 has much greater power than a saiyan's base or previous SSJ state. According to Goku, Gohan technically first transformed into this form during their training in the Hyperbolic Time Chamber. This scene was shown in a filler flashback in the anime, and it is shown that Gohan was too exhausted to maintain the form when he first transformed. This is the reason why Goku knew about this power before Gohan transformed into it during his fight with Cell. The first time the Super Saiyan 2 form was fully achieved and maintained by Gohan occurred after he witnessed the Cell Juniors' attack on the Z Fighters and Android 16's death at the hands of Perfect Cell.