|from B1 In Search of the Unknown, pg 25|
|from B1, pg 8|
TSR produced two official modules for Holmes Basic: the original versions of B1 In Search of the Unknown (1978) and B2 Keep on the Borderlands (1979). Each was included in the Basic Set at various times, and each was later revised for the next Basic Set. The original versions are essentially rules supplements for Holmes Basic, each providing clarifications and additions to the rules.
|The original 'monochrome' cover version of B1 from 1978. Source: Acaeum|
One oft-overlooked idea provided by the original B1 is an early version of "ascending" armor class. In the monster entries, the AC stat lists both the standard armor class (e.g. AC 7 = leather armor) and the number required for a 1st-3rd level fighter to hit such AC (e.g. a to-hit roll of 12). Obviously this idea was not taken up by TSR for use in other products and was almost completely forgotten. However, this format ("AC 7/12") is similar to how the modern OD&D retroclone Swords & Wizardry now records its armor classes, and are the same armor classes used in that game - the total of two numbers always equals 19.
|from the Swords & Wizardry WhiteBox Rules (3rd Print, 2010)|
from the Swords & Wizardry Core Rules (4th Printing, 2011), pg 72