Improving Your Mahjong: Beginners 3 (Reading Discards)
One of the basics in mahjong is reading the discards.
If you let your opponent win, it doesn’t matter how beautiful your hand could have been, you’ve lost.
That is why we need to try and understand what our opponent is doing by learning to read their discards…
1. Discarded tiles
The safest tiles are of course the ones that have been discarded. However, you have to be careful – not only one person might be waiting and their hand may change between a discard and your discard depending on positioning. The safest tiles are of course those that the player before you has just discarded. If someone doesn’t call it, then even if it is their waiting tile, they can’t call for it until play has proceeded one turn around the table.
2. Honor tiles where there are a lot on the table or in your hand
These can’t be used in runs, so their use is limited, making them relatively safer.
If you can see a lot of one of them, the likelihood is that it will be safe.
However, if there is an early reach, you need to beware of seven pairs (chitoitsu).
If there is an honor tile reach, or middle figure suit tiles are discarded before an honor tile, you need to be super careful!
Like in this example:
3. Discard tile Suji [Translator’s note: Sometimes referred to as piano keys]
Here is an example of a discard pile.
As is discarded, then we can deduce that the player is not waiting with 
or 
.
It then follows that 
and are relatively safe.
However, this isn’t correct in all cases as your opponent may not have a double-side wait.
If someone discards the , you should also look for 
on the table.
If you can see 4 of , they don’t have an end wait.
If you can see 4 of or , then they don’t have a middle wait.
If you can see 3 of , then they are not hoping for a head with two waits (shanpon-machi)
If you can see 4 of , they are not waiting on the head.
In the same way as discarded, 
is relatively safe.
4. When discards on the table create a wall
A wall is created when four of a tile is discarded. For example if you can see 4 of , then 
is a safer discard .
No one is holding a . Therefore any wait on the would have to be for a head.
If you can see , then the is only a ‘one chance’ for .
If an opponent does have the last , they would have to have .
Original Japanese link: http://www.ma-jan.or.jp/jan-up/class_1/03.php
