There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don’t know we don’t know. – American Sec’y. of Defense Donald Rumsfeld, 2002
A known known in today’s game is that 9. h3 ?? in the Classical variation of the Pirc Defense is a tactical blunder. White’s e4 pawn hangs to an attack on the White queen and White’s ability to snarfle thereafter Black’s pawn on b7 doesn’t compensate.
The unknown unknown in today’s game was the variation 14… Rxb2 ! 15. Bb3 Qe8 !!. I looked for a longish time at 14… Rxb2 15. Bb3 and the multiplicity of captures and discoveries of Black’s king’s bishop without seeing that after 15… Qe8 the move 16. Na4 doesn’t win the exchanged due to moves like Ne2+ and Qc6.
Like American policymakers in the 21st century, I was unable to shake my mind free from the immediate exigencies and focus on the whole of my position.
And like those same strategists manqués again, my desire to declare victory and go home led to the blunder 30. Qf6 ?? Luckily, my opponent was fixated on taking the hill with 31. Ng4 and overlooked the window of opportunity 31. f4 !! winning the bishop.
One known unknown in this position is that had White played a meaningless move on move 19, for example, 19. Nd1?? Black could have played 19… Qxh3 ! However, an unknown known just revealed to me by Stockfish 7 is that Black would be even better in such a situation after playing 19. Nd1 ?? Bh6 !!, e.g., 20. Qc3 Re2 21. Kf1 Bd2.
Dr. Leathwood is professional classical guitarist who has climbed about 300 rating points in the past 18 months. We expect great things of him.