Magic- Total Max
user Spells Spell
Level "Per Day" Level Other Memorization Limits
1st 1 1 -
2nd 2 1 -
3rd 2 2 no more than one 2nd level spell
4th 3 2 no more than two 2nd level spells
5th 3 3 no more than one 3rd level spell
6th 4 3 no more than two 3rd level spells
7th 4 4 no more than one 4th level spell
8th 5 4 no more than two 4th level spells
9th 5 5 no more than one 5th level spell
10th 6 5 no more than two 5th level spells
11th 7 5 no more than three 5th level spells
12th 7 6 no more than one 6th level spell
13th 8 6 no more than two 6th level spells
Total Spells "Per Day": The magician can keep memorized (i.e. prepared and ready-to-cast, as usual) no more than the listed number of spells at one time. These spells may be of any level or mix of levels known to the magician (but see Other Memorization Limits below). As usual, to memorize new spells, the magician must be well-rested. So effectively, the listed number is a limit on the quantity of spells that the magician can cast in one day.
Max Spell Level: The highest spell level the magician can memorize.
Other Memorization Limits: Due to the mnemonic challenge of mastering each new level of spells, only a fraction of a magician's spells "per day" limit can be used to memorize his highest level spells. He is not required to memorize any of his highest level spells, of course, but if he does, the stated limit applies.
So for example, a 13th level magician can memorize 8 spells at a time. He might choose to memorize two 6th level spells, plus six spells of 5th level or lower. Or he could memorize one 6th level spell, plus seven spells of 5th level or lower. Or all eight of his spells could be of 5th or lower level.
Less powerful? More powerful?
At low-to-mid levels, these variant magicians are certainly less potent in an absolute sense. But once the magician reaches 4th level, he is able to memorize more 2nd level spells at a time than would a normal 4th level AD&D magic-user: 3 for this variant vs. 2 for standard AD&D. While only modest at this point, the potential for leverage increases at higher levels. A 9th level variant magician can memorize far more 4th level spells than a normal 9th level AD&D magic-user: 5 vs. 2. And a 13th level variant magician can memorize eight 5th level spells, if he so desires.
If you use Bonus Spells for high stats...
Only use this if your system already grants magic-users bonus spells for high Intelligence. (The following rule isn't suitable for variant magicians in AD&D, for example.)
For systems that grant bonus spells for high Intelligence, even just a single bonus spell is worth a lot more in this variant system. Instead of increasing spells per day, consider raising the Other Memorization Limit by one, when Intelligence is sufficiently high. So an 11th level variant magician with a high Intelligence could still only memorize seven spells at a time, but now four of those could be 5th level.
Optional rule: Memorization "slots" are reclaimed only when the spell's duration expires
In other words, casting a spell is not sufficient to "clear room" in the magician's head for another memorized spell. In addition, the spell must end. So long duration spells (such as invisibility, which can potentially last many days) continue to "use up" a magician's memorization slot, until such time as the spell expires, or is canceled/dispelled.
As a minor point of counterbalance, the magician automatically senses when one of his in-progress spells has been terminated, no matter how far he is from the particular effect.