I think that the first wargame (in the full sense of the term) was Omaha Beachhead, of Avalon's Hill. An hex-map game designed at the battalion level. My second experience was with Command Decision and, tough I think it's a great game, by the time we played it I thought that it needed too much previous work. Funny think, in the present day I can spend months doing research and writing a new campaign. About Command Decision, a quarterly magazine was published titled "Command Post". All the fanatics of the ORBAT's (my first mysterious acronym discovered in this forum
) will find detailed lists of armies from WWI to the present day.
A little OT: Now it can sound strange, but in 1992 (when I purchased Command Decision) only a couple of stores exists in Barcelona specifically covering the world of roleplaying games and wargames. And the material was mostly published in English. Of course,thanks to internet I had access to great materials that were never published in Spain. Then I realized about the large extension that this world had reached long before the 90's in the US. Now I have gigabytes of material obtained by...shhhhhhtttt... those magical methods...
thanks to people that wished to share information that I should never be able to get.