7. Never attack the adversary’s king without a sufficient force; and if he attack yours, and you cannot retaliate, offer exchanges; and should he retire, when you present a piece to exchange, he may lose a move. It also may sometimes be expedient to act in this manner in case of other attacks.
8. Play your men in guard of one another, so that if any be taken, the enemy may also be captured by that which guarded yours, and endeavour to have as many guards to your piece, as your adversary advances others upon it; and, if possible, let them be of less value than those he assails with. When you cannot well support your piece, see if by attacking one of his that is better, or as good, you may not thereby save yours.
9. Never attack but when well prepared, for thereby you open your adversary’s game, and prepare him to pour in a strong attack upon you, as soon as your weaker one is over.
10. Never play till you have examined whether you are free from danger by your adversary’s last move; nor offer to attack till you have considered what harm he would be able to do you by his next moves, in consequence of yours.
11. When your attack is in a prosperous way, never be diverted from it by taking any piece, or other seeming advantage, your adversary may purposely throw in your way, with the intent that, by your taking the bait, he might gain a move which would make your design miscarry.
12. When, in pursuing a well-laid attack, you find it necessary to force your adversary’s defence, with the loss of some pieces; if, upon counting as many moves forward as you can, you find a prospect of success, sacrifice a piece or two to gain your end: these bold attempts make the finest games.
13. Never let your queen stand so before the king, as that your adversary, by bringing forwards a rook or a bishop, might check your king if she were not there, for you could hardly save her, or perhaps at best must sacrifice her for an inferior piece; as for example: place the white king on 61, the queen on 53; the black king on 4, and the rook, on 16: which last, if moved to 13, must be taken by the white queen, who in return would be taken by the black king, because the white queen could not otherwise be moved without putting the king on check to the black rook.
14. Let not your adversary’s knight fork your king and queen, or king and rook, or queen and rook, or your two rooks, at the same time; for in the two first cases, the king being forced to go out of check, the queen or the rook must be lost; and in the two last a rook must be lost, at best, for a worse piece. Place the white queen on 5, the rook on 7, and a black knight on 37. The latter piece, if moved to 22, will fork both the queen and rook, and consequently one of them must be lost for the knight.
15. Take care that no guarded pawn of your adversary’s fork two of your pieces: knights and rooks are particularly liable to this mode of attack; also guard against either a check by discovery, or a stale-mate.
16. When the kings have castled on different sides of the board, attack with the pawn you have on that side where the adversary has castled, advancing the pieces, especially the queen and rooks to support them; and if the adversary’s king have three pawns on a line in front, he should not stir them till forced to it.