THE ECHO
In Whist the play to a lead of a high and then a lower card is a signal for a lead of trumps, and is necessarily an indication of strength in trumps.
In Bridge this convention is used to show control of the third round of the suit led. Some players use this echo or signal to show that they can trump the third round of the suit, while with others it implies control of the third round either with the high card or by a “ruff.”
This signal should not be used except on your partner’s lead of king, as otherwise it would give information to the dealer. To use it on the adversary’s lead would help the dealer to make successful finesses, and to mark the distribution of the suits. Be careful when you use this signal not to echo with an honour. If you hold Q x, J x, 10 x, do not play the honour to the first trick; not only is your partner apt to think you have no more of the suit, but these honours are too valuable to throw away.
FORCING
To force is to make a player trump. This will, of course, reduce his trump strength and weaken his hand. It is as a rule good play to force the adversary’s strong trump hand. It will often prevent his exhausting the trumps, and hinder his bringing in an established suit.
The beginner hesitates to force the strong trump hand. He feels that he is wasting a high card and allowing the adversary to make a small trump, not realising that no card of this suit can make, unless the trumps are exhausted.
If no force be given to the strong hand, it is, ordinarily, an easy matter for the dealer to exhaust trumps and make a suit; unless there is unusual length in trumps, judicious forcing will do more than anything else to break down a strong trump hand.
Do not lead a suit with the intention of forcing the strong hand unless you hold the commanding card or can mark this card with your partner; you may give the dealer an opportunity to win the trick and to discard a worthless card.
You should hesitate to force when by doing so you establish the remaining cards of the suit for your opponent.