A key provision of the code was the "Right of Substitution", which allowed participants to select another to fight in their place. The Tellarite Naarg exercised this right to select Jonathan Archer as his replacement in the Ushaan against Thy'lek Shran.
One rule in the Code was that "Either combatant can postpone a duel indefinitely if there are no children to continue his clan." This did not apply to Archer, since he would have had to be married in order to make use of the clause. Another, that did apply, was that the Ushaan could be determined to be settled if an opponent was rendered defenseless. When Archer chopped off one of Shran's antennae with his ushaan-tor, Archer invoked this rule. (ENT: "United")