Well, these aren't commandments, but cautions, granted.
I found them in Living Age magazine, a weekly compendium of articles appearing in the U.S. and British press. This is from Volume 22, 1849. Although these dictums are well over a hundred years old, how many of them still apply today?
Cautions to Chess players, if not all original, yet all confirmed by our own experience :—
1. Chess not until the business of the day is fairly done, and you feel that you have earned your amusement.
2. Chess not in mixed society, when it is likely that your antagonist and yourself will be missed from the circle by either hostess or company.
3. Chess not with persons much older than yourself, when you feel sure that you can beat them, but not sure that they will relish it.
4. Chess not with your wife unless you can give her odds, and then take care rather to overmatch yourself.
5. Play not into the " small hours," lest the duties of the next day should suffer from scanty rest or late rising.
8. Do not commend your adversary's play when you have won, or abuse your own when you have lost. You are assuming in the first case, and detracting in the second.
7. Strive to have no choice as to board, pieces, &c., but, if you have any, never mention it after a defeat.
8. Mr. Penn recommends you " not to be alarmed if your adversary, after two or three lost games, should complain of a bad headache." We add—beware of attempting to alarm him by the like complaint in like case.
Lastly. Idolize not chess. To hear some people talk, one might think there was " nothing else remarkable beneath the visiting moon." Chess is not a standard for measuring the abilities of your acquaintances—nor an epitome of all the sciences —nor a panacea for all human ills—nor a subject for daily toil and nightly meditation. It is simply a recreation, and only to be used and regarded as such. The less selfish you are in its pursuit—the clearer head—the more patience— the better temper you bring to the practice of it, the better will you illustrate the merits of chess as the most intellectual of games, and establish your own character as a philosopher even in sport.