What's a gyroball?

Answers to your questions about the news.
Nov. 10 2006 4:11 PM

What the Heck Is a Gyroball?

A Japanese baseball pitch comes to America.

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Ace pitcher Daisuke Matsuzaka is being auctioned off by his Japanese baseball team this week. Early reports indicate that major-league clubs may be willing to pay $40 million or more for the rights to negotiate with Matsuzaka, who is supposed to be able to throw a mysterious pitch called the gyroball. What is the gyroball?

A breaking pitch that's similar to a slider or a cut fastball. (Click here for a slow-motion video.) What gives the pitch its mystique is how it came to be: The gyroball was devised by Japanese scientist Ryutaro Himeno, who described the results in his 2001 book Makyuu no Shoutai, which translates roughly to The Secrets of the Miracle Pitch. Himeno had been modeling the movement of different pitches on a supercomputer, then decided to use his equipment to come up with something new.

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The pitch he invented gets its name from its spin, which is like that of a football spiral. (Himeno calls it "gyro spin.") Most pitches in baseball either have topspin or backspin, but the gyroball spins sideways, like a thrown football or a bullet fired from a rifle.

There's some disagreement, however, about what the gyro spin actually does.

According to physicists, the gyroball should drop more quickly than a fastball. A standard fastball is thrown with backspin, which creates a lift force that keeps the ball in the air. A cut fastball has a lot of backspin with just a little sidespin to make it "curve," or break to the side. But the gyroball spins sideways with just a little backspin. That should make it break like a cut fastball and drop more quickly. (The gyroball won't drop quite as much as a curveball, which is thrown with topspin.)

In practice, the pitch may have more of a break than a drop. Baseball Prospectus writer Will Carroll, who has preached the gyroball's virtues for years, says he's seen the pitch curve 12 to 18 inches without much sinking motion at all.

Whether it has a sharp break or a big dip, some major leaguers and pitching coaches have dismissed the gyro as merely a variation on the cut fastball. The gyro has also been compared to a cricket pitch called the googly, which is also thrown with sidespin.

It's unclear whether Matsuzaka actually throws a gyroball. He's been evasive in interviews, saying that he might have thrown the pitch "sometimes accidentally." Carroll believes he saw Matsuzaka throw a few gyroballs during this year's World Baseball Classic. According to Himeno, at least two other Japanese pitchers use the pitch.

How do you throw a gyroball? According to Carroll, grip the ball between your thumb and your first two fingers, just as you would for a curveball. As you start to move your arm forward to throw the pitch, rotate your body toward home plate. On the release, press down with your fingers and twist inward to create the "gyro spin." This combination of body and arm rotation creates the right arm speed and angle for the best gyro spin. 

Explainer thanks Ryutaro Himeno of RIKEN and Alan Nathan of the University of Illinois.

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