The fortress is a very important tool which often allows us to save lost endgames. Sometimes, even strong players fail to spot simple fortresses. Of course, this fact has nothing to do with their chess level and understanding. Very often, people are just not on alert for a fortress.
The current article of Yochanan Afek starts with such an example.
One of the highlights of Tata Steel tournament last January occurred in the game between the American champion Sam Shankland and Netherland's No.1 Anish Giri in round 11.
In this position, Shankland (playing with Black) resigned. Instead, he could have brought his king to c8 and reach a theoretical draw. Here is how Afek takes on this fragment: What we witness here is a special type of positional draw where the inferior side, despite its significant material inferiority, builds up an impenetrable zone of protection. A proper fortress denies any king penetration, pawn breakthrough or Zugzwang.
In this article, the author deals with different types of fortresses. The article consists of 4 annotated examples, 13 interactive test positions (sorted by level of difficulty) and answer section in which all the test positions are explained.
After reading the present article and solving the test positions, you will definitely improve your defensive skills!