This is a proverb nobody ever explained to me, so I'm not sure that it doesn't apply to something altogether different. But I use it to remember the sequence below, so this is at least one possible interpretation.
Consider the following sequence (discussed by Sakata Eio in his book "The Middle Game of Go").
Black has just played the crosscut at . Sakata calls
vulgar style in the context of the discussed game, but that is another matter. There are plenty of occasions where this sequence is perfectly OK.
It is clear that is going to be captured. Nevertheless Black adds another one, in accordance with the proverb. White answers at
to keep the stones captured.
The thinking behind Black's line of play becomes clear in this diagram. Black has sente forcing moves at ,
and
. Compare this with an atari at
without adding the extra stone: White would capture (a ponnuki), and that would be the end of it. Adding the extra stone increases the liberties of the black group. As White needs more moves to capture it, Black gets more kikashi moves.
Note that Black must play fairly soon, even though it smells like aji-keshi. This kikashi slows White down by a whole move, i.e. changes a white move at a from sente to gote.
--Stefan
I think the whole point is that you are creating aji. Aji of one stone is less potent than a two-stone group that requires at least two more moves to kill, and can later reveal itself to be dangerous. All this for an extra move! 'Abandon' is maybe not the right word, but as it's impossible to completely figure a game out to the end, there's no way of knowing what those two stones can do, until it's within the near(er) future.
--Stevert (somewhere 'tween 10 kyu and 4 dan)
If White captures by playing the marked point, it's too easy for White. This is true for now or later. But if there is a Black stone at the marked point, then when White captures eventually the shape isn't as good. In fact later in the game when aji usually comes into play, the white stones may not survive.
unkx80: It might be instructive to elaborate on why the alternative moves for Black are not so good.
If simply ataris,
will capture and the block at a is no longer sente.
If simply blocks,
will capture and the atari at a is no longer there.
For the sake of discussion, if there is a stone, then White will almost always capture
by
(ladder), and almost never play
at a. This leaves only the aji at b, but the block at c is not sente.
Dieter: Let's look at three options. a, b and tenuki.
If Black at here,
can play tenuki.
ends in gote. Later there is the alphabetized endgame.
If Black does not play tenuki, he ends in gote. We can expect White a, Black b, White c in the late endgame.
Black gives up the possibility of tenuki and ends up in gote anyway. In the endgame we can expect Black a White b Black c.
If Black plays tenuki, can be sente.