Wait at ease for the fatigued enemy
Let the enemy make the first move. You may well have time to strengthen yourself.
Dieter: Rather than attempting to understand Ma's ideas than quoting him literally: this stratagem applied to Go means the following.
There are situations in which you want to do two active things. Two attacks, two cuts, two eye-stealing plays. The problem you face, however, is that the opponent can always answer flexibly, solving one of his two problems and giving you a problem in return. In such situations, it may be wise to strengthen yourself, letting him solve one of his problems on his own so that you strike at the other weakness without his having any compensation.
Lynx: It's lots of fun, of course, taking random sayings and manipulating them to fit into Go. The closest this gets is, in my opinion, that you should focus on keeping your own groups strong instead of blindly attacking. Then when your opponent tries to keep up, you have a solid base to fight with. This is all simple logic -- would you punch someone with a broken fist? -- yet hard to apply. Sad, isn't it?
This could apply when you play against someone with a handicap. Strengthen your area, make them attack.
Bass: This is a very useful stratagem for go. It has to do with assessing the relative strength of groups, which is all-important in choosing middle game strategy. The same group of stones with no definite eyes could be either a weak group when the opponent's nearby stones are strong, or a strong group when the opponent's nearby stones are even weaker, or something in between. It is important to know the difference, because defending an already strong group will result in an overconcentrated shape, while not defending a weak group will give the opponent an easygoing attack.
Here's an oversimplified example:
White has clearly left an invasion point in her position. White can play like this because black cannot launch a strong attack yet: the 4-4 stone would become lonely very quickly. (See SplittingMove for a possible continuation)