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A gyroball is a type of baseball pitch used primarily by players in Japan. It is thrown with a spiral-like spin, so that there is no Magnus force on the ball as it arrives at home plate. The gyroball is sometimes confused with the shuuto, another pitch used in Japan. ==Overview== The gyroball pitch was first identified by the Japanese scientist Ryutaro Himeno (姫野 龍太郎), and later developed into a specific throwing technique by baseball instructor Kazushi Tezuka (手塚 一志), who used computer simulations to create a new style of delivery intended to reduce stress on the pitcher. They published their work in a book, currently available only in Japan, the title of which is roughly translated as ''The Secret of the Miracle Pitch'' (魔球の正体). In simulations, they showed how a pitcher with good mechanics could throw the baseball in a way that it spun like a bullet or perfect football spiral, around the axis represented by the forward motion of the ball. This results in an unprecedented amount of "break" in the trajectory of the ball on the way to the home plate. However, the technique to throwing the gyroball is all in the arms, not in the unique grip of the baseball. Kazushi Tezuka is an instructor at the ''Jyoutatsuya baseball dojo'' in Tokyo, and Osaka, Japan. According to Tezuka, use of the arms "is the most important part of throwing the gyroball. It has nothing to do with the hands."〔(Brett Bull, "Unwinding the Gyroball," SI.com January 30, 2006 )〕 Amidst many conflicting claims, Tezuka says the gyroball has been misunderstood.〔Jeff Passan, "Finally, the gyroball mystery solved," Yahoo.com Feb 21, 2007 ()〕 In short, similar to a bullet, gyroball's axis of spin directly faces forward. According to Himeno and Tezuka, a gyroball is thrown so that, at the point of release, instead of having the pitcher's arm move inwards towards the body (the standard method used in the United States), the pitcher rotates his arm so that it moves away from his body, toward third base for a right-handed pitcher and toward first base for a left-handed pitcher. The unusual method of delivery creates a bullet-like spin on the ball with the axis of spin in line with the direction of the throw, similar to the way an American football is thrown. According to Tezuka, the pitch, if thrown correctly, is meant to fly straight like a fastball. Contrary to early speculation that the gyroball was a late moving breaking ball, the fact that the pitch travels with a bullet-spin denotes that the baseball is stabilized, hence the lack of movement. In baseball, most pitches are thrown with backspin, like the usual fastball, or with a more forward spinning motion, like the curveball and the slider. To throw a gyroball, a pitcher holds the side of the ball with a fastball grip. The pitcher's hips and throwing shoulder must be in near-perfect sync, something the book refers to as "double-spin mechanics." As the pitcher rotates his shoulder, he snaps his wrist and pulls down his fingers rather than flipping them over the ball, as happens with curveballs. The rotation is side over side. When the pitcher lets go, he must pronate his wrist, or turn it so the palm faces third base. It's like a right-hander throwing a screwball, only instead of the ball last touching the middle finger, it spins off the index finger. Batters use the arm speed of the pitcher and the spin on a baseball, made visible by the seams, to judge the speed and trajectory of a pitch. The gyroball is thrown with the arm speed of a usual fastball, but with a different actual speed. Its bullet-like spinning motion may hide the seams of a ball from the view of the batter, making it difficult to predict the pitch. Typical strategy entails throwing many variations of pitches, followed by a gyroball. The batter, predicting a change in speed caused by the ball's spin, may adapt to the wrong speed and swing incorrectly. The gyroball is also often confused with a completely different Japanese pitch called the shuuto, due to an error in a well-known article by baseball writer Will Carroll.〔Will Carroll,"The Ghost Pitch"()〕 Although Carroll later corrected himself, the confusion still persists. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gyroball」の詳細全文を読む スポンサード リンク
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