This diagram shows Sente's(先手） bogin attack. Gote(後手) just dropped a pawn at ３四. Can Sente(先手） do ２四歩?
It usually does work. However, in this particular example, Sente's King is in a wrong place.
What happens if you exange the Pawns and Silvers and let the opponent play his Bishop in 15? Check...
This is called outte bisha(王手飛車). Most players hate this. Some people even resign right here. As for me, maybe I do too.
Obviously, you now know that the King has to be well protected before attacking. You don't want your King to get trucked in the first few moves-of course, if you are not my son who likes go better.
The diagram here shows the two Kings both in tight defense. Mino gakoi(美濃 囲い=Mino Castle) is the one on top, and Funa gakoi is (舟囲い=boat castle)the one on the bottom. Each gakoi has their own strengths and weaknesses, but for now, please get used to these forms of defense.
I'll show you examples of some different gakois below.
All of these four Kakoi strategies shown here are Yagura (矢倉)variations.
You have already seen Mino (Black), but you still haven't seen Taka Mino(高美濃=Elevated Mino )!...which is only a few moves more than mino (White's formation)
In this diagram, the top one (White) is a completed Gin Kanmuri. (銀冠=Crowned with Silver) The bottom one (Black) is one move away. It has a lot of weaknesses and the opponent can attack and do vital damage. So the timing of doing this is very critical.
Notice how this Gin Kanmuri is an evolution of Takamino.
So, Mino gakoi can morph into Takamino, which can morph into Gin Kanmuri. Hmm. I have a feeling we are talking about Pokemon or something.
Finally, this diagram shows two forms of Anaguma (穴熊=Bear in a cave) gakoi. There is no way you get a stray bullett hit your King with this Kakoi. Drawback of this kakoi is that it takes many moves to build it. Also, The King has nowhere to escape once the Kakoi is compromised.
There are many other forms of Kakoi (or castling) It will be beyond the scope of this site to cover them all. See here for a collection of Kakoi (This is a Japanese site. There is a list on the left frame. You can click any item to see the different form of Kakoi - I will be adding how to navigate this site in the future)