This week, we shall follow up on last week’s 20 exercises with 2N vs. pawn.
Below I shall explain in some detail what challenges White are facing once White releases the reserve knight and the pawn is free to run down the board. There are 2 scenarios, depending on the placement of the Black king.
1. The Black king is in the upper part of the board
The four vital squares for White are b6, c7, f7 and g6. White needs both of these squares close to the corner to mate the Black king. Which is why knight’s and bishop pawns demand special attention – promotion on either b1, c1, f1 or g1 will affect the 4 vital squares. Sometimes, White has to come up with creative solutions, and all the different pawns for Black are represented in the 20 exercises.
This also explain why these pawns are less advanced in the Troitzky Line.
2. The Black king is in the lower part of the board
In this case, only one corner is affected, and I have chosen to show the a1-corner in the diagram above. The 2 vital squares here are b3 and c2.
If Black has an e-pawn, promotion on e1 to a knight could be a problem as it covers the c2-square.
If Black has a d-pawn, queen promotion on d1 covers both c2 and b3. Also, a pawn on d3 hits the c2-square.
A Black c-pawn is also disturbing in many ways, c4 covers b3 for a start.
The same goes for a b-pawn: it is disturbing too.
With the king in the a1-corner, pawns on the f-, g- or h-file do not disturb directly when promoted.
So, for the a1-corner, pawns on the files b-e can pose a problem. Similarly, if the black king is in the h1-corner, we have a mirrored case with pawns on the files d-g that could be a problem.