Voadam
Legend
Really? "To hit A.C. 0" is in the 1e DMG itself, appendix E the chart of monster stats starting on page 196.When THAC0 was adopted, the idea of hiding the AC of the target was basically gone from the game IME.
The 1e DMG IME is the height of hiding mechanics from the PCs.
"What follows herein is strictly for the eyes of you, the campaign referee."
"As this book is the exclusive precinct of the DM, you must view any non-DM player possessing it as something less than worthy of honorable death. Peeping players there will undoubtedly be, but they are simply lessening their own enjoyment of the game by taking away some of the sense of wonder that otherwise arises from a game which has rules hidden from participants. It is in your interests, and in theirs, to discourage possession of this book by players. If any of your participants do read herein, it is suggested that you assess them a heavy fee for consulting “sages” and other sources of information not normally attainable by the inhabitants of your milieu. If they express knowledge which could only be garnered by consulting these pages, a magic item or two can be taken as payment — insufficient, but perhaps it will tend to discourage such actions."