Tripod group  

Here is the tripod group as shown on the tripod group page. There is detailed information on how to defend against different attacks, but no mention of how this group might get formed. I found, for instance, the L group page very useful because it allows me to quickly realise if I can kill a group by making that shape. However, I don't see how I might be able to make life by forming the tripod group. So, when might a defender be able to force the tripod group?

White lives small  

The tripod group may occur as the result of a invasion under a shimari. When the outside is more valuable than the corner, allowing White to live small while Black makes outside strength is the correct direction of play. This example comes from Takemiya Masaki's book Enclosure Josekis, page 2.