3-01 Not all melds help your hand
International Tournament Rules do not severely penalize players for melding sets. It's true that you don't lose many points for exposing your hand, and as a result, many players believe that you should meld early in order to build sets quickly.
However, it is wise not to make the assumption that every meld is a good meld. Take Figure 1. You probably wish to build 567-678-789 Mixed Shifted Chows. And so, when the player to your left discards , you figure that it is a key tile to your hand, and happily claim it. However, there is a hidden disadvantage. Figure 2 shows your hand after claiming .
In order to build Mixed Shifted Chows, you need and . Picking or will improve your hand, but it will not make you ready for lack of sufficient points. Although it appeared that when you claimed you were left with two open-ended chows of and , in fact they are only 1-chance chows when the needed points are considered. In summary, early melds can in fact slow you down by limiting the possible hands that can be built.
Assume that you pass up the option to claim the and instead proceed with your hand fully concealed. Furthermore, assume that you picked several useful tiles, albeit not the precise tiles that you had wished for, and you have reached Figure 3.
What possibilities does this configuration offer?
With this hand, you can go out if you pick the last tile yourself, earning Fully Concealed (4 pts.) + All Chows (2 pts.) + Closed Wait (1 pt.) + Two Terminal Chows (1 pt.). Alternatively, if you draw or you can discard and go for a higher-scoring hand that will allow you to go out on an opponent's discard. In this way, you will find that keeping your hand concealed for as long as possible will allow for more possibilities.
Some players are reluctant to build a hand like the one shown in the above example since it is not possible to go out on an opponent's discard. However, do not forget that you gain at least 50% more points from picking your last tile. This somewhat offsets the disadvantage of having a hand that can only be self-drawn.