6. All fireballs and other offensive area effect weapons, have their damage points divided among all of those that are caught inside its limits. That means that if there are 4 people caught in a 6 dice fireball that does 20 points of damage on the dice roll, then each of the four takes 5 points of damage if they fail their saving throw, and 3 points (2-1/2 rounded up) if they make their save, NOT 20 point [sic] each!!!Among old schoolers, Arduin has a reputation for being both gonzo and deadly, so I was bit surprised to read the passage above, because it severely weakens the power of spells like fire ball. It's also an interpretation of area effect damage in D&D that I don't think I ever encountered back in the day. That's not surprising, since I didn't start playing till late 1979, by which point AD&D had been released and this issue, among others, had been definitively clarified. But back in '77, using only the LBBs, Hargrave's interpretation wasn't implausible (though examination of Chainmail would have shed further light on the matter).
I won't be adopting Hargrave's interpretation in my own campaign, but I like reading about rules variants like this. One of the great things about OD&D is the way that it unintentionally demands judgment calls and interpretations to make it playable. And Arduin, for all the things about it I dislike, is nevertheless a terrific example of one referee's "deciding how [he] would like it to be, and then mak[ing] it just that way!"