Brilliant! Look forward to the next episode. Thank you!
Applied Retrograde Analysis
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The Cryptic Quandary #1 - The awkward state of utter perplexity
In this first installment of the Cryptic Quandary series I’d like to focus on one of the many logical ways in which we are able to solve chess problems (or any problem for that matter), something called Retrograde Analysis (RA). According to Wikipedia, Retrograde Analysis is described as “a computational method used to solve game positions for optimal play by working backward from known outcomes (e.g. checkmate)”. The RA concept helps us frame 2 questions, what is it that we want to accomplish in a given position and how do we reach that goal?
The answer obviously depends on the circumstance but when honing in on the enemy King we reach a point where we’re searching for the decisive blow. RA can facilitate breaking down the current problem into smaller “chunks” and it’s probably what you’ve already been doing all this time when studying chess tactics but didn’t realize there’s a fancy name for it. An example of RA would be your mate in 2 puzzle book where we already know what the objective is (“what do we want to accomplish?”) and then “chunk” together attacking patterns on the King (“how do we get reach that goal?”) to find the checkmate. Unlike most pre-constructed mating puzzles, not all mating patterns are clear especially in tournament games (which is why Tactics Time by Tim Brennan is so much fun to practice tactics).
We can use this power of deductive reasoning to solve the following the position as an example. If you just want to solve it on your own please do, it’s a fun problem!
White to move (after 20 … Kh8)
There are obvious complications here:
All are valid observations but which one is most important?
Of course, the ultimate goal of the game would take precedence here. We have the black’s King squeezed in to a corner with a potential mate threat so #3 would make the most sense, and in turn, your synapses begin to fire and we immediately recognize we need to Remove the Defender. Notice black’s Queen doesn’t have a safe square to go to on the a3-f8 diagonal nor is there another piece defending it. Now is not the time to be passive, let’s apply the needed pressure.
The only piece able to attack black’s Queen is with our own Queen but which is the best attacking square for her? 21. Qb2 is no good because … Qxe3+ and our tempo is lost. There is only one square left for us to directly attack the enemy Queen without coming under fire from another piece, 21. Qd3!! now black has two choices either lose his Queen or get checkmated.
Black is forced to give up his Queen. His King-side is torn to shreds and white has sufficient material to defend any Pawn advancement on the Queen-side. The computer evaluates the position as +3 and should end up being a definite win for white.
Unfortunately, I never got a chance to find 21. Qd3 because I got too excited as I grabbed the Rook thinking I had the mate with 21. Rf8# then I realized the black Queen was defending f8. Since it’s touch move I had to move the Rook somewhere and any Rook move is a blunder so I resigned. However, I thought this would be a great puzzle as an example of applied RA.
Definitely check out Maurice Ashley’s Ted Talk on RA here which inspired me to write this article. I hope you enjoyed it.
Orgininal article here