As we discussed in the introduction, simply capturing a stone or stones is usually a move of last resort in a game. Usually it is more efficient to prevent the attacked group from living (so at the end of the game the stones are removed) and in the process surround a bit more territory.

As we know Black could have captured the White stone by playing in the triangled position but chose instead to play a different move:
The move played is making it a little more likely that the territory in the top left becomes owned by Black. It’s not yet certain but that is a discussion for later, on the topics of:

Capturing the White stone would have its merits but capturing it on a larger scale is even better. So is the White stone captured? It depends on the rest of the board.

Black’s stone in the lower right is crucial:
To understand why Black’s stone is crucial, the circles on the board map out the way that White is being captured on a large scale. Of course on a real board they are not there, but understanding that White is captured draws on two skills you will need to develop:
This diagram helps with the explanation:

White has tried to run away and Black has kept White inside those circles.

If White continues to run away eventually they will arrive at the rightmost circle and Black will capture all the stones by playing an enclosing (capturing) move.

However, that is not the end of the story.

White should not try to run away but counter-attack as shown:

Any move on one of the circled positions will act as a ladder-breaker.  This stone is both a ladder-breaker and also is starting to put some pressure on the Black stone in the lower right (Any move that does more than one thing is usually a good move).

Black will probably want to defend that corner and White has successfully protected the stone in the upper left (for now).

Should Black now try to capture White this is the outcome:

Worse, all those black stones can be attacked on the triangled points with a double atari. This is a very bad result for Black and unless something truly amazing happens Black has lost the game.

White’s ladder-breaker is also an attempt to force Black to capture the White stone using two moves when one would had done (so, doing three things, then). After Black has defended the lower corner White now has to decide whether to leave the White stone in atari or start the escape.

We are at a decision point in the game and if White decides to play elsewhere then Black is free to play on one of those circles so as to disable White’s ladder-breaker. And it all starts again.

This is a good time to introduce another book: “Lessons in the Fundamentals Of Go” by Toshiro Kageyama, 7P. It’s quite easy to find so here’s a review and almost every Go player will agree with what it says.

Here’s a precis on what he says about ladders:
…many are apt to become impatient when confronted by long ladders […] there is a widespread tendency to give up […] ladders should be the school that teaches you to read…
So this section concludes with a diagram adapted from Kageyama’s book and a question: “Is White trapped in a ladder?”