Smith Echo is a defensive signaling method (usually used only against notrump) and quite popular amongst experts.
Playing hi-lo in the first suit declarer plays says nothing about that suit. It sends a message about the suit the defense has led at trick one. Hi-lo means "I like the opening lead suit." Lo-hi means "I don't like it." This signal is used by both defenders and requires lots of judgment and inference. If count is important (for example, a long entryle
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