Sanshoku

Sanshoku used to be treated as one of the star yaku,
but in modern mahjong it has become more of a supporting role.

Still, it is a fairly easy 2-han yaku,
so there are plenty of situations where you will aim for it in actual play.
There are many very specialized techniques related to Sanshoku,
but only a limited number of them come up often in real games.

More than "forcing a Sanshoku,"
the important thing with Sanshoku Doujun is not overlooking one.
It is enough to remember the basic patterns.

1. Sliding

The basic idea of Sanshoku is to slide the manzu, pinzu, and souzu melds
so that they line up into the same number sequence.

Example 1

Let us start with a simple example.
Example 1 is a Pinfu one-shanten hand.

If you draw ,
you can swap it with and turn the hand into a 456 Sanshoku one-shanten.

In the same way, if you draw ,
you swap it with instead.

By sliding the pinzu block downward like this,
the hand becomes a 234 Sanshoku shape.
It is simple, but this is the most important basic technique for Sanshoku.

2. Balancing Two Options

This is a famous technique when aiming for Sanshoku.

Example 2

If you only value a wider acceptance here,
you would cut the pinzu block instead.
But the proper move is to discard .

In this shape, you can still aim at both 678 Sanshoku and 789 Sanshoku.
This kind of play is called "putting Sanshoku on a balance" or "the double-balance method."

That said, you do not actually get to use this very often in real games.