The fourth line is the line of victory
This proverb (citations of its usage needed) serves as a beginner advice that, on a common 19x19 board, pushing the opponent along the fourth line, so that the area underneath becomes his territory, is usually bad, or at least deserves to think twice about.
![[Diagram]](diagrams/49/12d23cddbf7631210cd32b2c9cc1df23.png)
Generally, Black being pushed along the fourth line gets more compensation in this pushing battle, compared to White's influence, accordingly 
is an uncommon approach to the 3-3 point. It is, however, played when the influence works well with regards to the rest of the board.
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