The use of a cue bid in the opponent’s suit, in response to an overcall by partner, to show at least a sound minimum raise of partner’s suit, thus releasing direct raises to be used competitively or pre-emptively.
West’s 2♣ bid shows three (sometimes more) spades and fair values (typically 10+ points). The bid neither shows nor denies a particular holding in opener’s suit, hence the name ‘unassuming’. West might hold:
