Spin

The Spin (回転) is a physical phenomenon and technique of primary importance to protagonists Gyro Zeppeli and Johnny Joestar in Part VII: Steel Ball Run.

The Spin may be considered counterpart to the Ripple power featured in the original timeline.

Summary
The Spin is described as the extension of a basic property of nature.

As demonstrated and explained by Gyro Zeppeli, the technique often involves the use of the phalanges, hand, wrist, elbow and shoulder, to the entire body (and beyond) in spinning a ball and/or launching it with the aim of exploiting the Magnus effect (whereby in flight, a spinning ball, by deflecting air flow, curves from its principal flight path), calculating trajectories with reference to golden rectangles in the environment.

Tools

 * See also: Steel Ball, Wrecking Ball and Tusk

Although a variety of objects are shown to be compatible with the Spin, Gyro prefers special Steel Balls; grooved, steel spheres characteristic of a baseball or boule, which he calls and shows to be something near the perfect tool for applying and maintaining Spin.

Gyro on one occasion is able to create a spinning sphere of water while underwater, deflecting Sandman's attack.

Johnny Joestar's Stand Tusk, developed with Gyro's mentoring, boosts his ability for applying Spin, namely by directly spinning his fingernails and allowing him to forcefully project them; which, closer to his body, may be better still than Steel Balls. With the fine Spin produced by Tusk, Johnny may punch spiral holes in himself, relocating damage, or his entire body, choosing destinations and targeting enemies to an accuracy resembling a guided or homing path.

Golden Rectangle
The Spin may be enhanced with reference to the Golden Rectangle (黄金長方形).

Recursively divided into a square and another golden rectangle, a line curved through the opposite corners (or centers, according to Gyro) of each square produces a golden spiral, which in theory continues forever. Emulating a golden spiral with a throw requires locating a golden rectangle as a reference in the environment (creating difficulty in an empty room or on a bare plain).

Super Spin

 * See also: Ball Breaker and Tusk ACT 4

The Super Spin represents the most faithful emulation of the golden spiral humanly possible, requiring a throw that includes the power of one's horse.

In Gyro's example: Allowing it to find a certain natural running speed, Gyro and Valkyrie form an extended golden rectangle, by which with his feet planted in his stirrups, Gyro may mount a supremely forceful, powerfully spinning throw.

A Steel Ball thrown with Super Spin can cut certain objects and on contact, numb an enemy's senses. Secondly, anything the Steel Ball hits will stick to it, as if attached.

Gyro's Ball Breaker and Johnny's Tusk ACT 4 appear representing the force of the Super Spin; both capable of bypassing the interdimensional barriers that hide and protect Funny Valentine and his Stand D4C.

Tactical vulnerabilities to this technique include that the horse requires a certain runway in order to find its idiosyncratic, "natural" speed, and the interception possible by slaying the horse.

Effects
Objects imbued with the Spin have a range of effects on humans, animals or the environment. While dependent on contact to inflict an effect, it would seem that the Spinning object does not actually have to be in motion in order to affect a target: For instance, during their initial meeting, Johnny's crippled legs twitch as he accidentally touches an inert Steel Ball that is spinning around its axis in Gyro's holster. As Gyro primarily uses the Steel Balls as thrown weapons, it is as such difficult to determine how much of their destructive damage is dependent on Spin alone. Use of the Spin has been shown for a wide range of destructive, defensive, medical and utilitarian purposes. Body manipulation with the Spin allows skin to be twisted so tight that it becomes bulletproof, entire limbs to be flattened, and on one occasion Gyro applies Spin to himself to wring water out of his body. The effect of Spin on muscle allows the user to contort, twist, and to a certain extent control the movement of others: during his introduction, Gyro wins a duel by manipulating his challenger's arm with a Steel Ball to the shoulder, causing the man's pistol-carrying arm to twist around until the man shoots himself in the head. While under the effect of Spin, muscles also seem to be able to contract more forcefully than they usually would be able to, as shown when Gyro hits Valkyrie's flank with a Steel Ball to initiate a sprint. In more destructive techniques, such as the ones employing Wrecking Balls, it has been shown that the Spin can cause temporary to permanent nerve damage, resulting in left-half ataxia.

Much like Hamon, the property of Spin is able to pass through certain things without visibly affecting them. This allows both for redirection of trauma (moving a wound from the hand to the leg) and damage (targeting a hostage with a Steel Ball, transferring the force and the applied Spin to their captor behind them). However, while Ripple attacks have been shown to transition through metal (see Metal Silver Overdrive) and stone walls (during Jonathan's fight with Jack the Ripper), only softer objects seem to be able to transfer the Spin. This is possibly due to how Hamon moves as arcs of energy in a medium, while Spin transfers through applying intrinsic rotational movement to the medium itself. During the battle with Sandman, it is revealed that Spin can also move through water, but its liquid nature ensures that the waves quickly dissipate. Trees and bark are susceptible to fine manipulation with the Spin (such as when Gyro creates an improvised rope during the battle against Dr. Ferdinand), but stone shatters.

Objects imbued with the Golden Rotation are shown to carry near-limitless energy, making for fearsome Spin-based attacks. Stands centered around Spin (such as Tusk or Ball Breaker) make use of this energy for supernatural purposes: Tusk ACT 2 and 3 is capable of spatial manipulation by moving a nail bullet hole using the Spin retained within it, and Ball Breaker uses the vast power of the Super Spin to simultaneously age cells in a target's body until the point of cell senescence.

The Spin has been long studied as a human anatomical corrective and medical treatment by the Napoletani Zeppeli Family, doctors renowned throughout Italy, although they are employed by their government as executioners, able as they are to effect clean, certain and painless death. While the medical application of Spin is only hinted to, its use is shown during preparation for an optical surgery.

Users

 * Gregorio Zeppeli
 * Gyro Zeppeli
 * Wekapipo
 * Johnny Joestar