Do You Know How To Analyse? Part 1

This is how Alexander Kotov described his play in the period 1935-36, before he gained the title of Grandmaster:

"My worst fault was an inability to analyse variations.".

"... most of the time mixing up variations and general reflections.".

"A lack of desire really to go into concrete variations thoroughly, a vague wandering about...".

I resemble those remarks! And this is how he set about remedying the problem:

"I selected from tournament books those games in which the greatest complications had arisen. ... I ... covered the page with a sheet of paper and set myself the task of thinking long and hard so as to analyse all the possible variations. ... Having spent between half an hour and an hour on this task ... I would compare them with those of the annotator.".

And here is how Kotov proceeds through the work of calculating variations:

"... I became even more convinced that the ability to analyse clearly a sufficient number of variations so as to clarify the position was the basic condition for succcess.".

1. "Candidate moves must be established straight away and they must be clearly ennumerated.".
2. The candidate moves form the 'trunk' of a 'tree of analysis', it's branches and sub-branches being the variations arising from each possibility.
3. "In analysing complicated variations one must examine each branch of the tree once and once only.".
4. It is important to analyse the optimum number of variations, so as not to spend too long or miss important lines. This, Kotov tells us, comes from intuition, and intuiton develops from practicing this method.

When practicing, this is of course all done either from a diagram or by setting up the position on a board and then analysing without moving the pieces.

Boleslavsky vs. Flohr, 1950
Position after 16. Rxe6+
Kotov position #6

The task in this position is to calculate the consequences of 16. ... Kf7 17. Rxf6+ gxf6 18. Qh5+. I'm looking for a suitable way to represent Kotov's tree of analysis diagrams in the blog-medium, but it goes something like this:

The candidate moves are 18. ... Ke7, 18. ... Ke6, 18. ... Kg7, and 18. ... Kg8.

A. 18. ... Ke7 19. Re1+
--A1. 19. ... Kd6 20. Bf4+ Kd7 21. Qf7+ followed by Re8+
--A2. 19. ... Kd8 20. Qe8+ Kc7 21. Bf4+ Bd6 22. Re7#
--A3. 19. ... Kd7 20. Qf7+ Kd6 21. Bf4+ Kc5 22. Be3+

B. 18. ... Ke6 19. Re1+ transposing into A1 or A2

C. 18. ... Kg7
--C1. 19. Qg4+ Kf7 20. Qh5+ is perpetual, but there is better...
--C2. 19. Bh6+ Kg8 20. Qg4+ Kf7 21. Rd7+ Be7 22. Qg7+

D. 18. ... Kg8 19. Qg4+
--D1. 19. ... Bg7
----D1a. 20. Bh6 Qc7 21. Rd7?? Qxd7 22. Qxd7 Bxh6+ loses, so
----D1b. 20. Qe6+ Kf8 21. Bf4 Rd8 22. Rxd8+ Qxd8 23. Bd6+ Qxd6 24. Qxd6+ or
---- D1c. 20. Qc4+ Kf8 21. Bb4+ both win.
--D2. 19. ... Kf7 20. Qc4+
----D2a. 20. ... Ke8 21. Re1+
------D2a1. 21. ... Be7 22. Bb4 Qc7 23. Qc5
------ D2a2. 21. ... Kd8 22. Qd3+ Kc7 23. Bf4+ Kc8 24. Re8+
---- D2b. 20. ... Kg7 21. Be3
------ D2b1. 21. ... Qc7 22. Qg4+ Kf7 23. Rd7+
------D2b2. 21. ... Qb4 22. Rd7+ Kg6 23. Qf7+ Kf5 24. g4+ Ke4 25. Qxf6
---- D2c. 20. ... Kg6 21. Qe4+ Kf7 22. Ba5 threatening Rd7+
------ D2c1. 22. ... Qc5 23. Rd7+ Be7 24. Bb4 Qg5+ 25. f4
------ D2c2. 22. ... Bh6+ 23. Kb1
-------- D2c2a. 23. ... Rad8 24. Qc4+ Kg7 25. Qg4+ and 26. Bxb6
-------- D2c2b. 23. ... Rhd8 24. Qxh7+ Bg7 25. Qh5+ and 26. Bxb6

The simpler looking lines are calculated first, and the more complex ones later.

It's a lot to look at and it appears daunting right now (and of course it's Kotov's analysis, not mine!)... but that's the point of the excercise.