How to Handle Dora (2)
Next, let us think about how to use up the dora that are already in your hand.
Example 1
Tsumo 
Dora
In Example 1, the dora is 
,
so you should cut 
.
The difference from cutting 
is whether the dora still remains usable if you later reach tenpai on a shanpon shape.
☆ Tsumo
☆ Tsumo
As shown above, if you choose the line that cuts ,
the dora gets pushed out in the end.
Example 2
Tsumo 
Dora
In Example 2, cut 
and lock in both dora.
You lose the Iipeikou this way,
but if you draw through 
,
a Menzen Pinfu Dora 2 hand waiting on 
through 
is of course better than a Menzen Pinfu Dora 1 hand waiting on 
through 
.
Example 3
Tsumo Dora
This is another shape that comes up often in actual play,
so it is worth remembering.
Cut 
so that no matter which kanchan fills first, the dora can still be used.
Example 4
Tsumo Dora
In a hand like this, it is important to reliably choose the correct discard.
Discarding a manzu tile is out of the question from an acceptance standpoint.
There is also a difference between cutting 
and cutting 
.
☆ Tsumo
☆ Tsumo
In the upper line, the dora gets pushed out,
but in the lower line you can riichi with two dora still intact.
Also, if you later draw 
to reach tenpai,
the line that cut
has the extra strength of letting you choose between a dora shanpon and a kan wait depending on the table situation.
Theory Summary
Build the habit of discarding in a way that uses up all the dora in your hand.
Original Japanese page: http://beginners.biz/dora/dora02.html