Recently, @ Kadano pointed out that Fox's chaingrab works longer if you, the thrower, have the port closest to P4. I am here to tell you this is because of a global difference in how characters throw each other depending on their port. Some have said the throw release point is different, but if they mean the X, Y position of your character when thrown is different, this is untrue and easily debunked.Here's what it is:The player with the port closest to 4 SKIPS the first frame of hitstun (and the first frame of the animation) from every throw.Below you can see Marth Up throwing Fox. This is the first frame that Fox is no longer in Marth's throw and is in the DAMAGEFLYTOP animation.The purple number at the bottom signifies X, Y position of Fox. Note that the Y position is identical. The velocity is applied exactly the same and the position he is in when released is exactly the same.The white number to the left is the number of frames in hitstun remaining, and the number next to DAMAGEFLYTOP indicates which frame of the animation they are in. You will see the second picture has 1 less frame of hitstun and is 1 frame further along the animation. As P2 being thrown I completely skipped over this frame.Above: Fox is P1 and Marth is P2Above: Marth is P1 and Fox is P2The implications of this are throw combos are better by exactly 1 frame for the player with the port closer to P4. In some cases they will be made possible, in others they will just be easier. Sometimes this may mean they are required to be in knockdown 1 frame longer and thus must tech when they otherwise may not have to. The advantage isn't crazy, but its there.Welcome to RPS for port priority. We just all thought it'd be for P1 rather than for P4.