How Verdict reads a touch

What is right-of-way, and why is it hard?

In sabre, when both scoring lights fire, the point doesn't go to whoever landed first by the clock — it goes to whoever had priority: the fencer who correctly started the attack, or who took it over with a parry or a well-timed counter. Reading priority means reading the whole phrase — who extended first, whether the attack fell short, whether a parry caught the blade — in a fraction of a second.

That's the judgment call referees train years to make, and the one that starts arguments at every club night when there's no referee on the strip.

How the AI makes the call

Verdict approaches the problem the way a referee does, in three layers:

• See the fencers. A pose model tracks each fencer's full skeleton — including the blade, down to the tip — at 94% keypoint accuracy, from a single camera angle. Footwork, extension, and blade position become measurable signals.
• Read the box. The scoring lights are detected directly from the video, so Verdict knows which lights fired and when. One light? The call is immediate — the light decides. Two lights? The right-of-way analysis kicks in.
• Judge the phrase. A temporal model trained on 23,500+ expert-labeled touches reads the sequence of movements — attack onset, distance, blade contact, timing — and determines who had priority, along with the action type: attack vs. counterattack, attack in preparation, parry-riposte, and more.

The actions Verdict recognizes

Every two-light call comes labeled with the action behind it, in the language referees actually use:

• Attack vs. counterattack — the attacker keeps priority; the counter arrives too late to steal it.
• Attack in preparation — one fencer strikes while the other is still setting up their attack.
• Parry-riposte — the defender catches the blade and takes priority with the answer.
• Remise and reprise — renewed attacks after a beat, and who they do or don't beat.

Because the call comes with its reasoning, every touch becomes a lesson — you see not just that you lost the touch, but why.

What Verdict needs from you

• A phone from the last ~5 years, filming landscape
• A sideline view with both fencers and the scoring box visible
• Normal indoor lighting — competition venues and club gyms both work

That's the whole setup. No sensors on the fencers, no wiring into the scoring box, no calibration step.