Wielding spells without that pesky memorisation-thing
There is no doubt that many attempts have been made to revamp or streamline the official OD&D spell-casting system. This article is yet another, but is intended not so much to build a better mousetrap, but more to make sense of spell-casting within the context of game "realism."
Our first concern is spell memorisation, as we believe that if a magic-user knows a spell well enough to memorise it, he should retain it after a successful cast. Our second concern is the predictable spells-by-level progression all casters follow, and we think a system to add some variation would be a helpful tool for players and DMs. Our final concern is the result of spell failure, which is hinted at in the rules, but not part of the spell-casting process as presented.
The system herein is completely optional, and while we find it useful, it doesn't necessarily fit into every campaign (or even a majority of campaigns). If you find the concepts below intriguing, we suggest applying them to the PCs and one or two NPCS for a few sessions before converting your campaign's spell-casting rules wholesale.
These guidelines are founded on a caster's Total Spell Levels (TSL), or the sum of all spell levels he can memorise at his current level, under the official rules. TSL can be thought of as the pool from which a caster draws his spell power, and while it would be an oversimplification to equate TSL with "spellpoints," the comparison isn't far from the mark.
A caster's TSL is based on the spell progression table for his class (cleric, RC/14; magic-user, RC/19; elf, as magic-user; druid, as cleric). Calculate the caster's TSL as follows:
The result is the caster's TSL, which indicates the maximum number of spell levels the caster can loose during a single day. For example, a 7th-level magic-user is allowed three 1st-level spells, two 2nd-level spells, two 3rd-level spells, and one 4th-level spell. The TSL is 8, as shown:
| Spell Level | Spells Allowed |
| 1 | 3 |
| 2 | 2 |
| 3 | 2 |
| 4 | 1 |
| Total Spell Levels: | 8 |
The caster may use only those spells contained in his spellbook (grimoires for magic-users or lectionaries for clerics). When a spell is cast, the caster's TSL is temporarily reduced by the level of the spell loosed; when TSL reaches zero, no more spells may be cast until the following day (or, at the DM's option, after 8 hours of uninterrupted rest). However, when a spell is cast, it is not forgotten, and may be re-used as often as the TSL allows.
To offset the ability to re-cast spells without memorisation, and the use of higher level spells than normally permitted, this system requires any spell-casting attempt to be arbitrated with an attribute check (called a spell check or spell roll).
As with other attribute checks, the spell roll's target number is 16, and the Difficulty Modifier is equal to the level of the spell cast. Casting magic-user spells is based on INT; casting druidic or clerical spells is based on WIS.
When a spell check fails, consult the Spell Failure table unless otherwise noted (see below).
A spellbook serves as a reference source for the caster. This is not spell memorisation in the same sense as outlined in the official rules, but more of a "refresher" or lookup, like that performed by a computer programmer who consults a manual to check a certain function or instruction set.
Each point of TSL per day requires a total of one hour of study (or prayer) per week. To simulate this during play, each spell-caster declares his intended number of study hours at the start of each game week; this is his daily TSL, up to the maximum allowed by experience level (see above). The weekly hours should be spread evenly throughout the week so that the character knows how long he has to study each day. Depending on circumstances and environment, it may be impossible for a caster to find enough hours in the day to reach his maximum TSL, and the daily TSL may be adjusted on a weekly basis depending on how much study time a caster can manage (you may require a minimum 8 hours of sleep per night in order to "recharge" one's daily TSL).
Magical spells are essentially recipes that combine mundane and arcane incredients into spell effects; these recipies are kept in a mage's grimoire. As a magic-user advances in his career, he may "invent" his own spell recipes (q.v., spell research).
Clerical spells are revealed to clerics as prayers and are kept in lectionaries. As a cleric rises in experience level, his lectionary grows through the addition of catechisms taught by the church or traditional prayers passed by his mentors.
When a spell scroll containing either clerical prayers or magical forumulae is discovered, a spell-caster may loose the spells directly from the scroll or copy the spells into his spellbook. Before either option can be exercised, the caster must read the spell(s) inscribed. All spell scrolls are written in ancient or dead languages (e.g., the campaign equivalent of Pelopenesian, Aramaic, or Latin). This requires either read languages or read magic, assuming that the caster cannot read the script through mundane means.
Invoking a spell scroll (i.e., casting a spell by reading it aloud) does not impact a caster's TSL or require a spell check. However, unless the caster already has the spell in his arsenal, it is typically wiser to add the spell to one's spellbook (N.B. the DM may rule that prayers on a clerical spell scroll may be unuseable by clerics outside the religion for which is was written).
When copying a spell from a scroll to a spellbook, the caster must make a successful spell check roll (as noted above). With a successful roll, the caster understands the spell and has copied it into his spellbook. If the roll fails, the duplication process turns out to be wasted time. Regardless, the magical script on the scroll fades.
Once a spell is copied into the caster's spellbook, it can be referenced and cast at any time. Using a spell requires a successful spell check roll (as above). If the roll fails, the Spell Failure table must be consulted immediately. Regardless of success or failure, the attempt reduces the caster's current TSL by the spell's level. As mentioned previously, when the TSL reaches zero, no further spells may be cast until the caster rests.
Players may balk at having to make a spell check roll for every casting, since spell-casting is automatically successful under the official OD&D rules. However, this practice helps to balance our spell-casting system. Its purpose is to prevent high-level spell-casters from hurling spells willy-nilly, and to preclude low-level casters from becoming too powerful. The DM should explain these factors to recalcitrant players; if complaints persist, the DM should point out that fighters have to roll whenever they swing their sword, thieves whenever they pick a pocket, and clerics when they seek to turn the undead. Given the need to roll for other class abilities, it seems fair that spell-casting follow suit.
For convenience, each spell-casting class's TSL has been calculated and is cited below:
Cleric and Druid
| Level | TSL | Level | TSL | Level | TSL | Level | TSL |
| 1 | 0 | 10 | 14 | 19 | 32 | 28 | 48 |
| 2 | 1 | 11 | 16 | 20 | 33 | 29 | 49 |
| 3 | 2 | 12 | 18 | 21 | 35 | 30 | 51 |
| 4 | 3 | 13 | 21 | 22 | 36 | 31 | 53 |
| 5 | 4 | 14 | 23 | 23 | 39 | 32 | 55 |
| 6 | 5 | 15 | 25 | 24 | 41 | 33 | 57 |
| 7 | 7 | 16 | 27 | 25 | 42 | 34 | 59 |
| 8 | 9 | 17 | 29 | 26 | 44 | 35 | 61 |
| 9 | 11 | 18 | 30 | 27 | 46 | 36 | 63 |
Magic-User and Elf
| Level | TSL | Level | TSL | Level | TSL | Level | TSL |
| 1 | 1 | 10 | 14 | 19 | 32 | 28 | 56 |
| 2 | 2 | 11 | 16 | 20 | 34 | 29 | 59 |
| 3 | 3 | 12 | 18 | 21 | 35 | 30 | 62 |
| 4 | 4 | 13 | 19 | 22 | 38 | 31 | 64 |
| 5 | 5 | 14 | 21 | 23 | 41 | 32 | 68 |
| 6 | 6 | 15 | 23 | 24 | 45 | 33 | 72 |
| 7 | 8 | 16 | 26 | 25 | 47 | 34 | 75 |
| 8 | 10 | 17 | 29 | 26 | 50 | 35 | 80 |
| 9 | 12 | 18 | 30 | 27 | 52 | 36 | 81 |