- The Reserves

Until the endgame, rarely all the forces take part to the various local battles on the chess
board. So, at some moment we may have active pieces and pieces that do not take part to
the respective actions. But this classification of active versus non-active pieces should be
conditioned as there are situations when the non-active pieces can enter the fight – this is
often spectacular and can be even decisive.

- Destroying the barricades

By setting a “barricade” one of the players wants to defend his position against an attack
toward his king, on one of the flanks, block an opponent free pawn and so on.
In fact, in almost any game, the players set up various barricades against opponent’s
active actions. We will see that in adequate circumstances even a barricade that looks
impenetrable can be destroyed or nullified.

A typical blocked pawn structure arises after the Old Indian Defense and some variations
of the King’s Indian and it is known as the “feather” structure.

Here, Black has 2 pawn chains: d6-e5 and d6-c5 with the same base at d6 and 2 heads at
c5 and e5. White’s pawn structure has 2 bases at c4 and e4 and one head at d5.
After some theoreticians, the “feather” structure is also when one of the black c- or e-pawns
are still on c7 or e7.
White cannot attack the d6-pawn directly, so his active plans are:
- Attack on the kingside by g2-g4.
- Attack against c5 by b2-b4, prepared by a2-a3.
- Attack against e5 by f2-f4, prepared by g2-g3.
Black has 2 targets, the 2 bases of White’s pawn chains, so his active plans are:
- Attack against e4 by f7-f5, prepared by g7-g6.
- Attack against c4 by b7-b5, prepared by a7-a6.

The theory about the play in endgames is often divided into several parts. Theoretical endgames are fundamental for our knowledge, because we need to memorize many different positions and understand them. The number of that kind of endgames is growing day after day. Without that basic knowledge we cannot play good in endgames.
Practical endgames are the second area, where it is important to understand certain positions. There are not many positions in the middlegame, that can transpose directly into a theoretical endgame. In the beginning endgames are usually complicated, but then they can be drawn into theoretical positions. But if we want to play them well, it is necessary to know some principles: these principles are especially meant for the endgames that are not theoretical. One of these principles is the principle of the second weakness, which is mentioned in every good chess book. The principle of the second weakness is one of the most important parts of realization of advantage in the endgames (Dvoretsky). The great Russian trainer described:” When the opponent is in a passive position, you have to attack different weaknesses. If you attack only one weakness, the player will be able to defend himself. It is necessary to attack other weaknesses. In most of the case we need to create the second weakness.”

There are two types of positions in chess, ones which require precise calculation, and others where you can largely rely on intuition and judgment. One of the common mistakes many players make is that they try to calculate everything, even at times when there is no need for it. By doing so, they spend a lot of time on the clock. This then cause them to end up in time trouble, which in turn results in mistakes or even blunders on the board. However, in this article, I would like to share with you some of my personal experience where actually calculation is crucial. In fact, the point is to calculate deeper and more precisely than the opponent.

In Spanish (Ruy Lopez) Opening, we have 2 pawn chains after the moves:
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0–0 Be7 6.Re1 b5 7.Bb3 d6 8.c3 0–0 9.h3 Na510.Bc2 c5 11.d4 Qc7 12.Nbd2 Nc6 13.d5 Nd8 14.a4 Rb8 15.axb5 axb5 16.b4 c4

6. a) White attacks with f2-f4, Black defends with f7-f6.
7. b) White attacks with f2-f4, Black counterattacks with f7-f5.

The co-operation between pieces (and pawns) can take many different forms, can be
evident or hidden, positional or tactical. Therefore, it is possible to make various
categorizations of the co-operation but this would be merely unpractical.

In fact, the only criterion to tell if there is a good harmony between pieces is the concrete
situation on the board.
The co-operation between pieces leads to even
paradoxical situations.