HAB: The Honors Asking Bid
We have a bid which asks how many of the top three honors partner has in a bid suit. This is a useful tool in a a couple of different auctions. Below is an example where the partnership has descovered a 4-4 heart fit after a Precison 1 opening bid.
South's opening bid is Extended Precision, showing 17+ points, and North's response shows at least 8 points but no 5-card major. The 2 rebid is Stayman, and responder's 2 rebid is Transfer Stayman, showing a 4-card heart suit and denying a 4-card spades suit. South has several optional calls at this point in the auction, and chooses to bid 2's, the Honor Asking Bid. With two of the top three honors, North uses a step bid - 3's - that's step 3.
Weak Two Bid Auction
Another possible auction where this can be used is this one:
Suppose your partner has opened a weak-two bid in hearts. We use a response of 2NT to ask for a feature, but we also use a HAB 3's to ask how many of the top three honors partner has in the trump suit.