"Hafgan held off on actually starting the fight, and the two met one year later. Pwyll was disguised as Arawn and the two fought properly this time. Pwyll still remembered the warning about Hafgan needing to be felled in one stroke. Arawn had explained that in the past when he had fought Hafgan and almost killed him, Hafgan had begged for one more hit. But this was a very clever trick by Hafgan! By taking anything more than one strike, he would recover as if he'd used magic and be able to fight again at full strength the next day."

It really was a smart strategy, and Eilonwy had asked how that had worked, but had never gotten any kind of explanation that worked for her.