Plane Sailing
Astral Admin - Mwahahaha!
I've been prompted to look up some of my earliest fanzines (what, me throw something away?) and the earliest one that I can find is Underworld Oracle issue 3 Nov/Dec.
No, they didn't put the year anywhere in it! I do know from issue 2 that it predates AD&D though... that issue gives a listing of the rule books as "Books 1, 2 & 3, Greyhawk, Blackmoor, Eldritch Wizardry, Gods Demi-Gods & Heroes, Swords and Spells".
OK, so we are resolutely pre-AD&D here. Probably Nov/Dec 1976.
Now, back to UO issue 3. The DMs Forum on p3 has an article about hit probability tables, making the observation that because the tables are regular, you can calculate an increasing bonus for PCs as they go up in levels, written by Phil Alexander.
Second column has the following text
So I submit to you that although this doesn't use the term THAC0, it is possibly the earliest point at which the concepts came together as a result of Gary Brittain and Phil Alexander.
Do I win?

No, they didn't put the year anywhere in it! I do know from issue 2 that it predates AD&D though... that issue gives a listing of the rule books as "Books 1, 2 & 3, Greyhawk, Blackmoor, Eldritch Wizardry, Gods Demi-Gods & Heroes, Swords and Spells".
OK, so we are resolutely pre-AD&D here. Probably Nov/Dec 1976.
Now, back to UO issue 3. The DMs Forum on p3 has an article about hit probability tables, making the observation that because the tables are regular, you can calculate an increasing bonus for PCs as they go up in levels, written by Phil Alexander.
Second column has the following text
Underworld Oracle said:Another aid for those whose memory for AC is not so good, recently appeared in Trollcrusher. Gary Brittain noticed that if one adds +2 to the score needed to hit AC 2 (i.e. AC 0 which is 19 for 1st level), then when combat ensues, if the AC of the target is subtracted from this figure, one has the roll needed to hit.
So combining the above, if you use 19 to calculate a 1st level's chance to hit AC 0, modify this with level step bonus (as a subtraction) and also subtract the AC being attacked, you have the roll needed to hit without consulting the matrix (see examples below).
If mental calculations do not appeal to you, there are alternatives that are just as easy and fast. A sheet prepared before the game showing the characters hit probability for AC 0 with strength and level alterations already taken into account, and perhaps magic weapons as well. All the ref has to do iin the course of play is subtract the AC and adjust if weapons relationships are used. if your players roll their own dice, they might add on their own bonuses as the DM subtracts the AC from 19, saving him a bit of work.
So I submit to you that although this doesn't use the term THAC0, it is possibly the earliest point at which the concepts came together as a result of Gary Brittain and Phil Alexander.
Do I win?
