You’ve read here before about the losing-trick count (LTC). Now I’m going to explain in more detail how it works.

The LTC applies to suit contracts. When there’s a suit fit, you want to establish how many losers there are in each hand. Typically, a minimum one-bid to start the auction shows seven losers. If responder has no more than seven, you’re probably in good shape to bid 4H or 4♠️ if a major-suit fit exists.

What counts as a losing trick? With a void there’s no LT in that suit. A singleton other than the ace counts as one LT; a useless doubleton, two. There’s one LT in a doubleton A-X or K-x.

In a suit at least three cards long — don’t count more than three losers in the suit — there’s one LT for each missing ace, king, or queen.

Let’s look at some examples. A-K-X? One LT. A-Q-X? One. A-J-10? Two because of the missing king and queen, but a repeated finesse might reduce them to one. Q-X-X? Without a jack support, the queen might not take a trick: three losers.

Sometimes LTC can be more useful than point count. In an Internet deal on OK Bridge, North was dealing with East-West vulnerable:

                                ♠️ 9 7 4 2
                                ♥️ A 7 6 5 2
                                ♦️ —
                                ♣️ Q 9 7 6

WEST                                                EAST
♠️ Q 3                                              ♠️ 6
♥️ K 10 4                                         ♥️ Q J 8 3
♦️ K Q J 5 3                                     ♦️ A 9 4
♣️ 8 5 2                                            ♣️ K J 10 4 3

                                ♠️ A K J 10 8 5
                                ♥️ 9
                                ♦️ 10 8 7 6 2
                               ♣️ A

The bidding proceeded as follows:

North            East             South              West
Pass               Pass            1♠️                Pass
2♦️ •            Pass             4♠️               All Pass

• Drury convention limit raise with four trumps (alerted)
Opening lead: ♦️K
Many players with the North hand would simply raise 1♠️ to 2♠️. With only eight LTs — three spades, two hearts, three diamonds — this North made a limit raise.  Holding only five losers — one spade, one heart and three diamonds — South’s choice for rebid was simple: 4♠️. When West discarded too many diamonds, North-South made six for +480 even though slam was not biddable.