I've read and re-read this a few times, and honestly I can't follow it. I am not educated enough to understand Yaw or to know what a seam halo is. But I categorically disagree that a riseball does not need backspin. That is, a true riseball. Not someone throwing a ball 70mph with a high trajectory.
Come on, Bill. Differentiating pitches based on seam patterns is pretty standard. A two seam fastball has a green center and two red bars. On a four seam fastball, the ball is a greenish blob.
With a bullet spin pitch, a batters sees a green center and the red swirl around the outside of the green. I don't like the term "seam halo" either...but it is better than "seam penumbra". I guess you could it a "seam ring".
We have a video of the Garcia throwing a bullet spin pitch. The batter was Washington's Amirah Milloy...a senior with a .319 batting average. Milloy played PAC12 softball in college, and west coast softball before that. She is a good hitter, and gets completely fooled. She swings and misses it by six inches.
Either (1) Milloy is so undisciplined that she swing at high fastballs or (2) it was a riseball.
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Due to the pandemic, I've watched the 2019 CWS finals a couple of times. Garcia keeps throwing something the Oklahoma batters swing under. Either the entire Oklahoma batting order sucks, or Garcia is throwing riseballs.
Go 2:13:00 of game 2 of the 2019 CWS and watch Garcia pitch to Shay Knighten. Knighten is one of the best hitters in college softball. Garcia starts her off with an outside fastball. On 1-0, Garcia throws something that Knighten swings under by 12 inches...it has to be a riseball. On 1-1, Garcia gives her another outside fastball. On 2-1, Garcia comes inside with a chest high fastball and Knighten murders it.