Improving Your Mahjong: Beginners 2 (Building a Hand)
After a cessation (due to my laziness). Here is another article translated from the JPML website.
The Basics of Building a Hand
The flow of mahjong is getting dealt a hand, drawing a tile and discarding a tile. This is repeated until of course someone wins or we run out of tiles.
First, discard any unnecessary tiles that are ‘floating’.
Tiles that are out on their own and don’t gel with any others or singular honor tiles should be discarded first.
For example: 
then the or an honor like 
if it isn’t a dora.
Slowly your hand should be taking shape. What do you do if you have a hand like the one below?
This is an “Extra Sets” hand (mentsuoobaa)
This means that if the potential sets (mentsu) were completed, there would be more than four (too many for a mahjong hand).
Let’s take as the head.
By removing that, we have six potential sets. Therefore, we have to choose one of these potential sets to discard.
So which sets are going to be difficult to complete?
(1) An end wait (penchan)
(2) A middle wait (kanchan)
(3) Waits where two tiles will be useful (nidouuke) and
The most difficult to complete is an end wait.
With an end wait , you can draw a 
to make a middle wait.
With a middle wait , you can draw a 
for a double-sided wait (ryanmen).
An end wait requires two tiles to be changed for a double-sided wait.
A middle wait requires one tile to be changed for a double-sided wait.
With the last example, even if a 
is drawn for , then one more tile (out of two options) is still required.
is also the same situation, but this is called Double Sets (daburu mentsu).
However, if you draw the and get a three-sided wait ,(3-menchan) before you are one tile to tempai (1-shanten), then we should keep it.
(1) Clear out unnecessary tiles
(2) Drop honor tiles that won’t be used
(3) If you have extra sets, clear from the least useful.
Original Author: Saori Atsuma
Translator: Gemma Collinge
Original Link: http://www.ma-jan.or.jp/jan-
