THE ECHO
Some players use the echo only when they can trump the third round of a suit.
The echo is a signal used by Bridge players to show ability to win the third round of the suit either with a trump or a high card.
If your partner leads the K and then the A when you hold only two cards of that suit, show you can trump the third round by playing first the higher and then the lower.
If you hold the Q and your partner leads the K and A, show in the same manner that you can win the third round of the suit.
Don't echo with an honour; it may deceive your partner.
At "no-trump" the echo is used to encourage partner to continue that suit.
On a doubled spade, if your partner leads a high trump, echo with three by playing the intermediate trump to the first round.
THE DEALER'S PLAY WITH A DECLARED TRUMP
In playing the two hands, the dealer must take advantage of any information he can gain from the leads and plays of the adversaries; and, in return, try to convey a false impression of his own hand. Above all, the dealer should know the score and estimate the number of tricks he must take to win the game; always bearing in mind that if he cannot win the game, he should try to prevent the adversaries from so doing.