If you think that you and your partner have enough points to bid for a slam it can be essential to know that you have enough aces (and kings) - to avoid the embarrassment of losing that vital trick to an ace held by the opposition. It is possible to hold enough points and still be missing an all important card.
This is where the Blackwood bidding convention comes into its own. It is a way of asking your partner how many aces (and/or kings) they hold, to ensure that you have enough high cards to make the contract.
You can read more about Blackwood and see how it works if you click here.