A doubtful double should not be made when the partner has another bid, as, for example, when the adversary to the right has called four Hearts, over three Royals declared by the partner. Under these circumstances, the double, on the theory that the doubler expects to secure a large bonus, may properly deter the partner from a successful four Royals declaration. Even when the double is successful to the extent of 100, that is not a sufficient compensation for losing the opportunity to win the game.
The fact that a good player has declared an unusually large number of tricks, as, for example, five Hearts, is not in itself a reason for doubling. A player of experience, when he makes such a declaration, fully realizes the difficulty of the undertaking. He does not take the chance without giving it more consideration than he would a smaller bid, and it is only fair to assume that he has a reasonable expectation of success. Doubling, therefore, merely because the bid requires ten or even eleven tricks, is folly, pure and simple. This comment, however, does not apply when the bid is of the flag-flying character.[21] As to whether or not it comes within that category the doubler will have to determine. The Auction expert is always on the lookout for an opportunity to gather a large bonus at the expense of a flag-flyer, and as unduly sanguine players indulge in that practice more than others, their declarations should be subjected to the most rigid scrutiny.
The doubtful double, which, should it prove unsuccessful, will result in the Declarer scoring a game he would not otherwise obtain, is, as a rule, inexcusable. By this is not meant that a bid of two or three Hearts or Royals, or of three or four Clubs or Diamonds, should never be doubled. That would be absurd doctrine, but such a double should never be made with the chances even, or nearly even. An experienced bidder will not risk presenting the adversaries with the game and a bonus unless reasonably sure of defeating the declaration.
Another absurd notion is doubling because of the partner's general strength. The partner has an equal opportunity to double, and is much better posted in relation to his own cards. If the strength be his, he should decide whether or not to take the chance. When, however, one partner has some strength in the suit the adversaries have declared, and the other, high side cards, the double is more apt to confuse the Declarer if made by the player without the Trump strength.