Ladder escape
In the ladder situation below, the piece h8 is a ladder escape, or an escape piece.
It allows Red (the attacking player) to jump a move ahead of the ladder and win the game. Red can play along the ladder, forcing Blue's response at each step. After move 9 at g8, Red is connected to the bottom.
A ladder escape can be thought of as a little boost for the attacker, giving them just enough extra space to get past the defender's chain.
However, it is not necessary to have an escape piece on the projected path of the ladder in order to escape it.
Third Row Example
In this example, Red has no third row ladder escape piece. Red 1 provides an escape by threatening to connect to the main group.
After the sequence to Red 3, Blue cannot stop both of Red's non-overlapping connections.
Second Row Example
In the example below, Red 1 threatens to connect to the main group either via Red's second row ladder or higher up.
After the sequence to Red 7, Red can now connect 5 back to the main group through either of the spaces marked with *.