Kaio-ken Kamehameha (界王拳・かめはめ波; lit. "World King's Fist Turtle Destructive Wave") is a combination of the Kaio-ken technique and the Kamehameha used by Goku. Goku activates the Kaio-ken technique and uses the Kamehameha, inflicting extreme damage depending on what Kaio-ken level he is using for the attack. The only known Kaio-ken levels he used for the attack are Kaio-ken x3, Kaio-ken x4 and Kaio-ken x20.
Visually, the Kaio-ken Kamehameha is almost identical to a standard Kamehameha. The only noticeable difference is that the energy wave is larger and much more powerful. As the Kaio-ken multiplier increases, the wave gets larger.
Main article: Vegeta Saga
After being battered around by Goku's Kaio-ken x3 attack, Vegeta ends up losing his temper. The Saiyan prince then flies up in the air and launches his Galick Gun, intent on destroying Goku along with the Earth. Out of fear of letting the blast hit the Earth, Goku uses the Kaio-Ken x3 Kamehameha to repel the Galick Gun. Seeing how both attacks are evenly matched, Goku uses the Kaio-ken x4, surging through the Galick Gun and blasting Vegeta into the sky. However, Goku's body is left exhausted and weakened from having used so much power.
The World's Strongest
Main article: Dragon Ball Z: The World's Strongest
Goku uses the Kaio-ken x3 attack against Dr. Wheelo (which broke off one of Dr. Wheelo's claws) and then launches a Kaio-Ken x3 Kamehameha against the giant robotic scientist. After a brief Beam Struggle with Wheelo's Planet Geyser, Goku increases it to x4, allowing the blast to destroy Wheelo's lab fortress and send him into outer space.
Main article: Frieza Saga
During the fight with Frieza, Goku gets thrown underwater by the tyrant, who attempts to drown him. However, after seeing a vision of his friends and family being murdered and Earth destroyed, Goku regains courage and raises his Kaio-ken to x20, the highest Kaio-ken level. Goku then beats around Frieza and fires a gigantic Kaio-ken Kamehameha at the tyrant, who manages to block it, causing only slight damage to him. The blast was named x20 Kaiken Kamehameha in Dragon Ball Z: Budokai Tenkaichi 3.
Main article: Dragon Ball Z: Cooler's Revenge
Seeing as he was no match for Cooler in his final form, Goku uses the Kaio-ken Kamehameha against the tyrant. However, unlike his brother, Frieza, who was damaged by the attack, Cooler simply surges through the blast and attacks the surprised Goku.
Appearances in games
Goku can use Kaio-ken Kamehameha in the Gokuden series, Dragon Ball Z: Shin Budokai - Another Road, Dragon Ball Z: Budokai Tenkaichi 3, Dragon Ball Z: Burst Limit, the Raging Blast games, and Dragon Ball Z For Kinect. He has versions ranging from x2 to x20 (x2, x3, x4, x10, and x20 Kaio-ken Kamehameha) in the Gokuden series, he uses the Kaio-ken Kamehameha x20 in Budokai Tenkaichi 3, the Raging Blast series, and Dragon Ball Z For Kinect.
In Dragon Ball: Xenoverse, the Kaio-ken Kamehameha appears in cutscenes during the game's Return of the Saiyans Saga where it is used to counter Vegeta's Galick Gun like in the original history. In the Xenoverse cutscenes, Goku uses the x3 and x4 versions during the historic Energy Clash with Vegeta's Galick Gun. Though the Kaio-ken Kamehameha does not appear as a skill, it is possible to use the Kamehameha and other Kamehameha skills (Super Kamehameha, x10 Kamehameha, Perfect Kamehameha, etc.) in conjunction with the game's 3 Kaio-ken transformation Super Skills (Kaio-ken, x3 Kaio-ken, and x20 Kaio-ken) by entering the Kaio-ken state via one of those skills and then preforming a Kamehameha.
- In Budokai Tenkaichi 3, the x20 Kaio-ken Kamehameha is spelled as "x20 Kaiken Kamehameha".