How to approach a weakness that is difficult to play with?

[Uberdude]

I just followed a link to this old thread and thought I could add a nice example of how to play against the san-ren-sei. One of my students asked about this very topic and I gave a group lesson on it on KGS. As an example I used a game of mine from OGS in which my opponent played san-ren-sei and I simply beat him by 25 points. He didn't make any blunders, just a few dubious strategic decisions and a few soft moves. I think it nicely illustrates the various issues:
- There is no need to be jealous of your opponent's moyo. It is a common mistake to invade too early or think you will lose if your opponent gets a lot of his moyo. Go is a sharing game, just make your share a little bigger.
- A moyo on only one side of the board is nothing like as good as a two-dimensional one that spreads over 2 or more sides. So making strong white positions on the top and lower side restrict any future development of the san-ren-sei and will aid future invasions.
- Thickness is best for attacking weak groups, so if you can avoid giving your opponent a weak group to attack his thickness rather goes to waste.

Here is the lesson on KGS (the simple 25 point win game is the top variation, there is a 2nd game in there which illustrates the strategy of making a bigger moyo as white, leading to fighting and mutual destruction: in the end half of black's san-ren-sei dies and white's left side is reduced to a 2 point group!):

http://files.gokgs.com/games/2011/10/20/Uberdude.sgf

And here is the game with a review on OGS that should be easier to follow but doesn't have all the variations and in-depth discussion of the lesson:

http://www.online-go.com/games/sgf/268/268009-162_gomad361-vs-Uberdude.sgf