North opens the bidding 1♦ and East overcalls 1♠. Sitting South, we have a lovely 6-card heart suit but only 6 high card points. We want to do something but aren’t strong enough to bid hearts.
Luckily, we have the negative double which will ask partner to bid one of the unbid suits. North now bids 2♣ and when it comes back to us, we must decide what to do.
Even though partner has already bid twice and hasn’t shown any hearts yet, should we bid 2♥ now or just choose between clubs and diamonds?
Would bidding a new suit now force partner to keep bidding?
Read more about negative doubles in bridge here: https://learnbridgeonline.com/negative-doubles-in-bridge/