Tips and tricks
2nd and 4th row parallel ladder escape
Suppose we have this situation. There are parallel ladders on the 2nd and 4th row.
Red to move. Can she win? The answer is yes: Red can win by using Tom's move!
How to block properly (by lazyplayer)
If your blocking move has too little influence on both of your edges, then the opponent has at least two good board areas that are worth trying, one on each side. For example, compare the situation for Blue in these two cases.
In this case, the initial blue pieces (E9 and F7) have very little influence on both of Blue's edges and thus don't provide any immediate threat on the bottom. Blue has no choice but to play D8, which however is still far from being connected to either of Blue's edges.
This position, on the other hand, is quite a bit more tricky for Red to play correctly. Blue is still too focused on the bottom (unavoidably, given the weak position), but after having obtained a reasonable amount of influence on the right side, he can now concentrate his efforts on the left side of the board.