Situational Judgment Basics
What Is Situational Judgment?
Beginners tend to look only at their own hand.
But as the hand progresses, you can gather many kinds of information from the table.
Taking that information into account before deciding what to discard, whether to call, or whether to riichi, is what situational judgment means.
If you keep looking only at your own hand, it is easy to miss important information.
To put it bluntly, that is just "picture-matching mahjong."
Mahjong requires many different skills, but situational judgment is one of the most important of all.
Even hand-building changes depending on the situation.
For example, it is standard mahjong wisdom to dislike a penchan more than a kanchan.
But even that can reverse depending on the situation.
For instance:
Table info: 
three copies are already visible
In that case, you would keep the penchan instead.
To go even further, from this hand it could also be completely correct to cut or .
And if it were haitei, it goes without saying that you should discard the safest tile.
If is guaranteed to pass, then you simply cut .
Mahjong only becomes real mahjong because situational judgment exists.
The most important part of situational judgment is whether to attack or defend against the opponents' hands,
in other words, push-fold judgment.
That topic belongs in the final chapter.
In this chapter, let us first think about hand-building that takes the situation into account.
The Two Kinds of Situation
Situational judgment is not actually that complicated.
There are only two kinds:
table situation and score situation
The table situation means what is happening on the board itself.
What the dora is, the discard rows of all four players, who has called, whether you are dealer or non-dealer, what turn it is, and so on.
All of that belongs to table situation.
The other equally important part is the score situation.
Because the result of mahjong is decided by the score when the game ends,
you always need to keep the points of all four players in mind.
Situation and Strategy
What matters is building a strategy from those two kinds of situation before you play.
Do you actually think that way during real games?
For example, if there are already 4 riichi sticks on the table,
then a natural strategy is: win quickly and take those sticks.
If the player in first is dealer, then aiming for a high-value tsumo can be an effective strategy.
If it succeeds, the dealer-payment structure lets you close the gap even more.
So before speed and efficiency and everything else,
strategy comes first.
Even with an opening hand like this, there can be several different correct approaches.
- If you are dealer in East round, you might take the nine-terminals abortive draw.
- If you are far behind in last place, you might keep both Kokushi and Honitsu in mind and start by dealing with tiles like .
- If you are in first place in South 4, you might preserve the Kokushi skeleton so that you can fold at any time.
All of these can be valid strategic choices.
Original Japanese page: http://beginners.biz/joukyou/joukyou01.html