|— Bang to Fuhrer Ugly|
After being defeated by his older brother Bomb in the past, Bang abandoned his old fighting style, the Exploding Heart Release Fist, and many years after, he invented Water Stream Rock Smashing Fist, the ultimate defensive art, while studying with his brother. The scars all over his body and his spectacular skills testify to the harshness of his training and the intense battles he surmounted.
This style involves understanding and re-creating within one's body the flows of torrential and undulating forces, putting this into the user's fists. When used by a skilled fighter, this martial art is very effective and powerful, especially against humanoid opponents, and as long as the opponents are of a certain size that martial arts can still affect them. When in use, a blue aura can be seen around the user's extremities. Charanko describes this style as "leading enemies around the nose by moving like a calm stream, only to finish them off with a punch strong enough to smash great rocks like a raging river", implying that Water Stream Rock Smashing Fist parallels real-life Tai Chi. Genos describes it as "the perfect blend of offense and defense". Users of this martial art can repel the attacks of their opponents or redirect them with twice the power.
It is possible for the user to redirect attacks that are significantly more powerful than the user's own strength, as seen when Garou was able to deflect many of Metal Bat's blows despite taking a single one may leave him incapacitated. However, it has a limit for redirecting force, as in the user cannot deflect attacks that have too much power behind, in comparison to the strength of the user themselves. An indication of this is that, after deflecting Metal Bat's Savage Tornado technique, Garou's hands were shaking due to the impact of the S-Class hero attacks. Furthermore, this is clearly seen when Garou failed to deflect Superalloy Darkshine's tackle using the style, with Garou himself commenting that the hero's charge was immensely powerful.
Users of this martial art are capable of deflecting small dust particles, rapid blade attacks, and even attacks of pure energy. Furthermore, when in crisis, it allows the user's body to move on its own. Initially, it is noted by Genos and stated by Superalloy Darkshine that Garou's mastery of this style is not on the level of Bang at all. Nonetheless, the Hero Hunter has managed to sharpen it throughout his battles, being able to fight on par with his former master later while in his evolved state.
- Water Stream Encampment (流水陣, Ryūsui-jin): Performed by Bang. He creates an area where his fists destroy anything that enters, protecting those inside. First used to shield Genos from falling meteor debris. He later uses this defensive technique again to fend off many clones of Black Sperm surrounding him and Tanktop Master.
- Instant Movement (瞬身功, Shunshinkō): Performed by Bang. Bang jumps at his opponent using special footwork, elegantly and quickly moving as if he were flowing. He then confuses them with a swift feint before performing a fast piercing attack. He precisely aims for the enemy's weak points from places they cannot predict. First used against Melzargard.
- Fang Interpolation (牙挿指, Gasōshi): Performed by Bang. Using the fingertips that he has trained, he can hit the smallest weak points with single hits of incredible accuracy. This move is known to be smooth like water but powerful enough to destroy rocks with unparalleled destructive power.
- Allsight (見切り, Mikiri): Performed by Bang. By training his dynamic visual acuity and anticipating the enemy's movements, he is able to demonstrate the terrifying power of Allsight. He can catch and pierce even the quickest of enemies with precision. Bang is seen using this technique against Melzargard.
- Awakening Breath (剛醒呼法, Gousei Kohou): A breathing technique that exerts one's body to the utmost limits. After being performed, the user's physical stats are temporarily increased. Bang has used this technique to prepare for his fight with Elder Centipede, so Bomb and Genos could escape with the unconscious heroes. He is later seen using this breathing technique again to save Tanktop Master from Gums, and when he is fighting Garou in his evolved state.
- Whirlwind Water Stream: Roaring Aura Sky Ripping Fist (旋風流水 轟気空裂拳, Senpū Ryūsui: Gōki Kūretsu-ken; Viz: Whirling Wind Flowing Water: Fist of Roaring Qi, Rending Air): A powerful technique that combines both Water Stream Rock Smashing Fist and Whirlwind Iron Cutting Fist. To perform the technique, Bang and Bomb stand side-by-side and assume strong stances. Both perform their respective martial arts and strike the opponent simultaneously, sending powerful shockwaves through the opponent's body. The technique was powerful enough to knock back a charging Elder Centipede and shatter the monster's carapace. However, as stated by both Bang and Bomb, they can only do this technique once in a while due to their old age. Traditionally when the technique connects, the shockwaves created will spread through the victim's entire body, which ultimately reduces the victim to dust.
- Whirlwind Water Stream: Cross Fang Dragon Slayer Fist (旋風流水 交牙竜殺拳, Senpū Ryūsui: Kōga Ryūsatsu-ken; Viz: Whirling Wind Flowing Water: Fist of Biting Fangs, Killing Dragons): A combination of the martial arts of Bang and Bomb, even more powerful than Roaring Aura Sky Ripping Fist. Both perform extremely powerful strikes at their opponent with their respective martial arts during combat.
- This martial art is one of the main fighting styles that make up the Monster Calamity God Slayer Fist.