I have been asked for a Microlite74 version of the Mnemonic Mage optional class from Tarnhelm’s Terrible Tome (my set of house rules for S&W and other 0e games). Here is a first pass at a Microlite74 Mnemonic Mage class and the rules for mnemonic magic. Mnemonic Mages are standard Magic-Users who use mnemonic magic instead of the standard arcane magic. The class description is for Microlite74 Extended but with minor modifications it could work with other versions of Microlite74 (and possibly with Microlite81). These rules have not been playtested, but they are based on 0e rules that have been used for many years.
The following text is Open Game Content under the OGL.
Mnemonic Mages (Arcane Class) wear no armor and can only use daggers, slings or staves as weapons. Physical Combat Bonus is level/4, round up. Magical Combat Bonus is level/2, round up. Experience Base is 30. Class Saving Throw Bonus is +1. They add +2 to WIL saves. They cast Mnemonic spells and have the Minor Magic and Arcane Blast special abilities. A Mnemonic Mage cannot cast spells through ritual magic although he may perform special rituals (that do not duplicate spells) through ritual magic.
A Mnemonic Mage has a number of memory slots to hold spells equal to his level plus one. A Mnemonic Mage memorizes spells by reading them in his spell book and forcing them into his mind. The number of memory slots (MS) a specific spell takes up depends on the class of the spell. Minor Spell: 1 MS; Lesser Spell: 2 MS; Greater Spell: 3 MS; Extraordinary Spell: 6 MS; Most Extraordinary Spell: 12 MS. Forcing a spell into memory takes 10 minutes of spell book study per memory slot required by the spell and costs HP equal to the memory slot cost of the spell. To cast a memorized spell, all the Mnemonic Mage needs to do is to recite it. This releases the spell from his memory and causes it to take effect. Once cast, the spell is no longer in memory.
Mnemonic Spells: The Minor spell class includes spells from the first and second level magic-user spell list. The Lesser spell class includes spells from the third and fourth level magic-user spell list. The Greater spell class includes spells from the fifth and sixth level magic-user spell list. The Extraordinary spell class includes spells from the seventh and eighth level magic-user spell list. The Most Extraordinary spell class includes spells from the ninth level magic-user spell list.
First level Mnemonic Mages start with a spell book holding 3 minor spells, 2 lesser spells, and 1 greater spell. The player may select two of the minor spells from those the GM allows were available to the mage during his apprenticeship, the others are selected by the GM by whatever method he wishes.
10% of the arcane scrolls and spell books found as random treasure should contain spells in mnemonic form. These items are useless to a standard magic-user. Scrolls and spell books with spells in standard (non-mnemonic) form are useless to a Mnemonic Mage. A Mnemonic Mage may either copy a mnemonic spell into his spell book from a scroll or memorize the spell; in either case the spell fades from the scroll after one use.