Forcing Chess Moves: The Key to Better Calculation

Brute Force combinations

Study material

In the introduction, we defined the two core aspects of developing

powerful computer eyes. The first task was accurate brute force analysis of

variations, and the second was overcoming human bias in order to become

more objective, and creative, in our ability to find unusual winning forcing

moves.

The term ‘brute force’ refers to the way machines ‘think’. While

computers analyze scores of variations and then try to draw conclusions,

humans have a tendency to conceptualize positions first, with concepts

like ‘weak pawn’, ‘open file’, ‘better development’, etc. This is natural and

okay, but the problem comes when we make decisions based on such

generalizations, without first testing their validity with concrete analysis.

Developing computer eyes means learning to analyze essential forcing

moves first, and always basing our final decisions on well-considered

analysis.

When the supercomputer Hydra crushed the incredibly strong English

GM Michael Adams in a 2005 match, an age-old debate was put to rest.

Many had believed that positional judgment or ‘grandmaster intuition’

could overcome brute force calculation of scads of variations, but we now

know that accurate brute force analysis is the single most important chess

skill.

In Chapters 1 and 2 we began by training your computer eyes to become

aware of recurring stock sacrifices, helping you recognize critical attacking

positions and get in the habit of examining the most forcing moves first.

At the same time, we began to examine the crucial role of brute force

analysis and creativity in unearthing these powerful combinations.

Having gained a basic knowledge of stock themes, you are now ready to

learn how to better calculate the original, uncharted ‘bread and butter’

situations which occur most often in tournament play.

Even ‘straightforward’ brute force variations can be very difficult to

calculate accurately, because this analysis requires three essential skills:

1. Accurate ‘board sight’ – the ability to correctly envision where

the pieces are, and what they can do, even deep in the midst of a long

calculation.

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2. Accurate ‘selection’ – the ability to hone in on the key options, and

avoid two key pitfalls at the opposite ends of the spectrum: failure to

consider unexpected, but crucial ideas; or wasting huge amounts of time

analyzing ‘dead ends’.

3. The raw ability and effort needed to calculate variations.

Fortunately, these skills can be developed through practice, problemsolving, the study of master games, and by gaining a deeper understanding

of forcing moves.

In this chapter we examine three types of brute force combinations:

A) ‘Bread and Butter’ Brute Force combinations

Most tactics books concentrate only on mating positions like the stock

forcing moves found in Chapter 2. But these positions are relatively

unusual in club play, compared with ‘bread and butter’ tactics: 2-4 move

deep combinations winning material. Some of these combinations may

utilize stock ideas in one or two side variations, but the primary focus is

on accurate brute force calculation.

B) Mating and ‘Hybrid’ Brute Force combinations

This section is devoted to mating combinations which are too unique, or

require too much original brute force analysis, to be considered ‘stock’

ideas; and ‘hybrid’ sequences in which both mate and/or win of material

figure in the calculation of different variations.

C) Promotion-based Brute Force combinations

Combinations involving actual pawn promotion, or the achievement

of mate or material gain via the threat of promotion, could constitute

a worthwhile book by themselves. A strong awareness of these motifs

is certainly a key aspect of developing your computer eyes, and we will

revisit them many times, as they relate to different chapters of the book.

A) ‘Bread and Butter’ Brute Force combinations

FCM 3.1

Karthikeyan-Vachier-Lagrave

Gibraltar 2019

._._._T_

_J_.jMt.

J_Sj.j.l

_._N_I_.

._._BbSj

_.i._._.

Ii._.iI_

_._Rr.k.

131

Chapter 3 – Brute Force combinations

The critical position has arrived in this tense queenless middlegame.

White is clearly better after 1.♗xh6 ♘xh6 2.♘f4 ♖b8, but as a practical

matter he must calculate a long forcing sequence which may knock off his

famous opponent decisively:

1.f3! ♗xf4

The other messy try also required bold calculation: 1…♘ge5!? 2.♗xh6

♖xg2+ 3.♔h1! (surprisingly 3.♔f1 only draws: 3…♖g1+ 4.♔e2 ♖1g2+ 4.♔e3

♘c4+ with a perpetual) 3…♖2g3! (threatening mate; inadequate is 3…♖xb2

4.♖b1 ♖xa2 5.♘c7! with the crushing fork threat 6.♗d5+) 4.♘f4! (better

than 4.♗f4 ♖h3+ and 5…♘xf3) 4…♖h8 5.♘h5 ♘xf3 6.♘xg3 ♘xe1 7.♘e2,

winning.

2.♘xf4 ♘ge5 3.♗d5+ ♔e8 4.♗xg8 ♘xf3+ 5.♔f2 ♘xe1 6.♗d5!

White had to visualize all this, as well as Black’s last-ditch next move, to

choose the right line. If 6…♘c2 7.♘g6! snuffs out all counterplay before

corralling the knight with ♖c1.

6…♖g5 7.♔xe1 ♖xf5 8.♘g6 and 1-0.

Similarly here, evaluation of the critical position turns on a brute force

shot.

FCM 3.2

Gostisa-Robatsch

Ptuj 1995

T_D_._T_

j._LmJ_.

Sj.j.s._

_.jIj.j.

I_I_I_._

_._N_QiI

.i.n._Bk

rR_._._.

If Black had one more move, he could establish a fortress with …♖g6 or

even take the initiative with …g5-g4. But White strikes first, destroying

the integrity of Black’s set-up:

1.♘xe5! dxe5

White has a solid extra pawn and more after 1…♖h8 2.♖f1, while on 1…g4,

2.♕f4! gxh3 3.♖f1 is very strong.

2.d6+! ♔xd6

2…♔e6 3.♕f5+.

3.♕xf6+ ♗e6 4.♘f3 Black is in tatters: 1-0.

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Forcing Chess Moves

In messy, wildly complicated positions the only way to deduce that a

position is ‘critical’ is often to find the winning line! In tactical minefields,

every position is essentially critical:

FCM 3.3

Short-Zagrebelny

Dhaka 1999

._._._._ ._._._._

_.tL_M_J

._.s.d._

_._I_J_.

.j._.i._

_._._.qI

._._._Rk

_R_._._.

The old coffee-house saying ‘Always check, it might be mate!’ could be

usefully amended as follows: ‘When many checks are available, computer

eyes carefully calculate each one, mining every line for potentially

winning brute force sequences’.

Four succinct and accurate checks bring home the point here:

1.♕g8+ ♔e7 2.♖g7+

The quickest and most efficient, although here or on the next move,

2/3.♖e1+ would also have won.

2…♘f7 3.♖xf7+! ♕xf7 4.d6+ Prying king from queen – 4…♔e6 5.♖e1+; 1-0.

Even in relatively ‘simple’ positions, calculating one move deeper or more

precisely often makes the difference: