Disclaimer: I am god-awful at chess.

I

Late-beginner chess players, those who are almost on the cusp of being basically respectable, often fall into a particular pattern. They've got the hang of calculating moves ahead; they can make plans along the lines of "Ok, so if I move my rook to give a check, the opponent will have to move her king, and then I can take her bishop." and those plans tend to be basically correct: the opponent really does have to move her king.

But there's a very important rule to follow when calculating. Always end your calculations after your opponent has moved. You must never end your calculations after your own move. In other words:

The enemy gets the last hit

This principle is common in cyber security: you have to let your red team make the last move. If your red team finds a vulnerability, and your blue team patches it, then you have to red team the patch. It's the same for AI red-team-blue-team games: I recall a story of a team at one of the MATS streams, presenting their final work on some AI control (or similar) protocol:

Audience member: But why didn't [...]

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Outline:

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(03:56 ) III

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First published:

November 23rd, 2025

Source:

https://www.lesswrong.com/posts/dz54kTLNAex9cRqzg/the-enemy-gets-the-last-hit

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Narrated by TYPE III AUDIO.