“You must take your opponent into a deep dark forest where 2+2=5, and the path leading out is only wide enough for one." – Michail Tal
I am looking for ways to systematically find lines where one player is forced to find series of precise moves.
The battle of Thermopylae was fought in 480 BC between the Achaemenid Persian Empire under Xerxes I. and an alliance of Greek city-states led by Sparta under Leonidas I.
During two full days of battle, the small force led by Leonidas blocked the only road by which the massive Persian army could traverse the narrow pass.
The performance of the Greek defenders is well known as an example of the advantages of training, equipment, and use of terrain as force multipliers.
In chess, I consider a 'thermopylae' to be an only-move that must be found by ones opponent in order to not blunder away their game. Similar to the historic example, it is a narrow pass, an only road, and when studied and prepared at home, it gives rise to a possible advantage through training, equipment, and use of terrain. (You get the point...)
Consider the equal position given below where Qd1 is a thermopylae from blacks view since both Qd2 and Qd3 (and every other move of course) lead to a significant advantage for black.
[fen "rqr3k1/3n1ppp/bp2pb2/1N1p4/PP1Q1P2/2P1BR2/4B1PP/R5K1 w - - 0 1"]
In the equal position below, white needs to find Be4 to not blunder away the game. If this is found, the game 'widens' after Ke6, but remains 'narrow' after Nb4, asking again for precise moves from white.
[fen "r4r2/5k2/3p4/2pn4/2R5/p7/2B2PPP/1R4K1 w - - 0 35"]
Is there a way to (have engines) systematically go through tabiae (the ends of opening lines) and extract lines that lead to such thermopylaes, possibly a multitude of these down a certain line? (I understand this will include a number of trivial recaptures and forced moves, but I'll go with that.)