Ultiworld Ultiworld DG

Principle of Verticality

I haven’t often heard the principle of verticality being used as a valid reason that a certain play is a foul. I have the feeling that many players who get a foul like this called on them use the argument that the play was completed before the principle of verticality was violated (i.e., player 1 caught the disc in the air above player 2 before player 2’s vertical space was impeded).

Does anyone have more insight into this? When can a player successfully appeal to the principle of verticality as the reason a foul occurred, even if the player causing the infraction caught the disc?

“The Principle of Verticality: All players have the right to enter the air space immediately above their torso to make a play on a thrown disc. If non-incidental contact occurs in the airspace immediately above a player before the outcome of the play is determined (e.g., before possession is gained or an incomplete pass is effected), it is a foul on the player entering the vertical space of the other player.”

If a player has a play on the disc (able to jump high enough without being impeded to catch it) and contact happens such that the player’s ability to make that play was impeded before the outcome of the play is determined (disc caught by opponent, swatted away where the player couldn’t get to it, etc), the player has been fouled. It doesn’t matter if the player impeding the opponents jump would have caught it first or could jump higher, etc.


I think I’m going to print this out and staple it to my rulebook; just to be official about it.

Just to clarify what Mitch wrote (which is 100% correct and quotes the rulebook), the Principle of Verticality is never violated by merely entering the airspace over another player. There is no violation if a player managed to jump completely over another player without contact. The Principle of Verticality functions to assign blame for contact that occurs in that vertical space, but without contact there is no blame to assign. Note: Without the Principle of Verticality, jumping up into another player would be a foul on the later jumping player (he is initiating contact with a legally positioned player he could have avoided by not jumping).

A couple relevant examples:

  • Disc goes up. Player A jumps, catches the disc, then lands on top of Player B. Not a violation of Principle of Verticality. The outcome of the play was determined. It may be a dangerous play (on A) or a blocking foul/dangerous play (on B) depending on whether A knew his jump would result in dangerous contact or B took their position such that they knew A would hit them.

  • Disc goes up. Player A and Player B both jump for a disc between them. Each player is only entitled to assert the principle for the space immediately above them. If they jump horizontally and contact results other than directly above them, it’s not a violation.

  • Contact can also still be incidental to the outcome of the play. If the contact didn’t actually affect Player B’s jump. If the disc was uncatchable even without contact (e.g., flies over both players’ heads). In those cases, the Principle doesn’t apply.

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