Extending on Third or Fourth Line

This is often the most difficult decision to make, and the answer depends on both what you are extending from and what you are extending towards. Furthermore, it also depends on your overall strategy. Here are some guidelines:

• If you are worried that your extension may be cut or that your group may come under attack - extend on the third line.
• If you are worried that your opponent has gained too much influence towards the centre or that you are too low - extend on the fourth line.
• If you are extending between your own positions - extend on the fourth line.
• If you have a solid position along the side which you want to use to develop your influence - extend on the fourth line.
• If you are trying to create a living group or you are invading - extend on the third line.

See also

• Know Your Lines
• Fourth line vs third line
• Classical example of center versus side territory