In order to defend well you have to work together with partners. Specific agreements are important, but “high-level” agreements are also important. Your philosophy on how we work together and how we signal is the most important part of this.
(478) Defensive Carding: Dummy has Qxx+
(477) Defensive Carding: More Suit Preference
(476) Defensive Carding: Suit Preference Signals
(475) Defensive Carding: Smith Echo (Reverse)
Against a NT contract, when the opponents win the first trick and attack another suit they are often leading their best suit. In this case, we have an opportunity to communicate with partner. Smith Echo is an agreement that makes use of this situation to tell partner if the opening lead was good or not.