Why does Pure Straight score more points than Mixed Triple Chow?

Both Pure Straight and Mixed Triple Chow are nine-tile chow-based combinations. So why, you might ask, does Pure Straight (16 points) score double the points of Mixed Triple Chow (8 points)?

Figure 1

Both the and are key tiles. Which will lead to a higher-scoring hand?


Consider Figure 1. You are one tile away from going ready on either Mixed Triple Chow or Pure Straight. All you need to do is pick the right tile to connect to the or . Picking a or is preferable to a or , since the Pure Straight (16 pts.) scores more than a Mixed Triple Chow (8 pts.) + Outside Hand (4 pts.).

Figure 2

Picking will lead to higher points. But a different choice allows you to complete your hand faster

Why would a Mixed Triple Chow score less than a Pure Straight? The answer is because Mixed Triple Chow is a more flexible combination. Take Figure 2. In order to go for the higher-scoring hand, you must discard a dot or bamboo. But this decision results in a hand which hinges on filling the edge wait by picking . The choice which offers more flexibility is trashing the edge wait, , and attempting to build a 789 Mixed Triple Chow. Even if you pick a , you will be able to make use of it with by picking or on a subsequent turn. Either of these tiles will allow you to shift to a 678 Mixed Triple Chow. Furthermore, picking or allows you to pursue Mixed Shifted Chows. To build the Pure Straight, you must either pick or claim it from the player on your left. In comparison, Mixed Triple Chow offers far more flexibility, and is thus rewarded less points.

Figure 3

A commonly-seen pattern can be seen in Figure 3. You are one away from making ready, and the Pure Straight is very tempting. However, rather than discarding and building a Pure Straight, we recommend discarding . This discard allows you to make ready by picking , and puts you one tile away from various states of readiness as seen in Figure 4.

Figure 4

Formations of Figure 3 after one turn