Losing Trick Count
The Basic Premise Probably the very first thing new bridge players learns is how to count their points, but after a bit of experience they finds that the rules for how many points are needed for a particular contract are often inaccurate. Well, there's help, and it's called Losing Trick Count. LTC is not perfect, but it's a vast improvement over pointcount bidding for some types of deals. It works best for unbalanced hands where there is a fit and at times it will be the only way to reach a game or a slam. It's also a rather simple way to evaluate a hand. LTC does not replace the need to count points, but instead is used as an adjuvant to your pointcount method and can be very accurate. Pointcount bidding works best with balanced hands playable in notrump contracts, but you will find that LTC is better for suit contracts. This is the LTC formula:
How to Count Losers Count only the top three honors that are missing in each suit. A doubleton has only two losers and a singleton (other than the singleton ace) has but one loser. Jennifer Jones, who has written extensively on this subject uses these examples:
An Example Hand West opens the bidding 1 and you hold the East hand. Most players holding the East hand will give their partner a limit raise, which many West players will pass. What do you think are the chances of the two hands making game?
West opened with a poor 13 count and if you count the points in the East hand you find 11. East has a hand for a normal limit raise which is generally in the range of 1012 points. But count the losers in the two hands 
East has 2 spade losers, 2 in hearts, 1 in diamonds and 2 in clubs which is also a total of 7 losers. A normal opening bid has 7 losers, which is the LTC for the West hand, and which East should generally expect as a minimum. East should presume a total between the two hands of no more than 14. Subtracting 14 from the magic number of 24, leaves 10; the expected number of winners. East has enough for game and should not stop short! If East gave his partner a limit raise many West players would not want to bid higher.
Adjustments It would be nice if it were as simple as the description above, but it isn't. Some adjustments have to be made. Why? Because there is a world of difference between the two hands below that both have an initial LTC of 8.
From your own bridge experience you know how powerful aces are, and you know that queens can be valuable, but aces and queens are not equal in strengh. Here's the adjustment to compensate for that difference 
Another LTC Adjustment West opens 2NT, showing an unlimited pointcount and 5+5+ in the major suits. How many Losing Tricks does East have? Actually, making adjustments is a lot more complicated than this, but you would need a calculator and a table of suit combinations with predetermined values to work out the math, so making good estimates will usually work just fine. The Adjustment Rules above are only an approximation, but will probably suffice. If you want a bit more, consider this:
Clearly not. What about AJx and AJ10?. should both be two losers? Equally clearly, no. So, there are some rules for adding extra accuracy to the LTC. The concept of the Losing Trick Count hand evaluation is about as simple as the pointcount method, but experienced players who use it will tell you it is more accurate for judging a hand after a fit is found. Points are important, and are usually a very good guide to how many tricks a hand can take in a notrump contract, but LTC has an implicit method of considering distributional values that works well with suit contracts. After you get used to using it you will probably find yourself bidding more aggressively and making contracts that others do not reach, especially when you have a fit with your partner's suit. In that sense the concept is related to the Law of Total Tricks.
