Saruken

Saruken (サるけん, Monkey Fist) is a taijutsu technique invented by Ryun Mazuka. As it's inventor, Ryun is the only person ever able to successfully use it. The Saruken is a technique that multiplies the user's chakra for a "heart beat", enabling them to inflict serious damage to opponents who are considerably stronger than them. After the introduction of the Saruken, it became one of Ryun's signature attacks. While using it, Ryun will use the demon ape's cloak.

Description
To use the Saruken, the user's base chakra level must double for an instant by use of the Four-Tailed Beast, however, Ryun later learns to increase the effect of the Saruken to higher multiplications. With it, palm thrusts can send small blasts of air that can throw and opponent back, and contact of a punch can cause massive damage. The technique however has its substantial flaws, such as if the user multiplies their base chakra too much, the up rise of chakra could easily obliterate them, or severely damage their body, as it did Ryun's.