There have been very few positives to 2013, but Hiroki Kuroda's Cy Young caliber season has made every one of his starts worth watching. I don't think it's necessary to rattle off all the statistics, but he's been completely dominant in the toughest division in baseball. Through designated hitters and the tiny ballpark of the East Coast, one could argue that Kuroda is one of the best pitchers in baseball. This season, he's demonstrated a splitter that's particularly dirty. I've noticed that depending on the spin angle of the pitch, Kuroda has earned different movement. This is something the Freddy Garcia has grown famous for, controlling a splitter that actually swings based on seam orientation, as opposed to the magnus effect. Although Kuroda doesn't get the same movement into left-handed hitter's that Garcia does, the pitcher looks to have the ability to control a lot of the movement in to right-handed hitters.
Below are the same two splitters highlighted.
Finally, here is what the pitch looks like when it owns very little break into the right-handed batter's box.
You can see that the seams of the ball are constantly cutting the air on both the 1 O'Clock and 7 O'Clock sides of the ball. The spin isn't as efficient as Garcia's, but it does appear that minor swinging action occurs. By this, I mean that the rotating seams are creating opposing turbulent and laminar air forces on the ball. The results are an unexpected drop and break, similar to the effects seen on a knuckleball.