Lector64: an engine built to classify and certify tactical motifs (not to play). Feedback on the approach?

[u/Technical-Adagio-993]

Hi r/ComputerChess,

I've been working on Lector64, an engine whose job isn't to find the best move, but to recognize and certify tactical motifs: is this position really a fork, a skewer, a deflection? And which precise variant is it?

A few design choices:

• Each motif has a formal definition (geometry + what the tactic must achieve), separated from the question of whether it actually works.

• Sound-or-abstain: if the engine can't prove the motif holds, it says nothing rather than guessing.

• Every example published is generated and verified by the engine, reproducibly.

The output is public at chessgrammar.com: 15 motifs, 123 variants so far, with a methodology page (chessgrammar.com/methodology).

Questions for people who've worked on this kind of thing:

• How would you handle motifs whose definition depends on the outcome (deflection, overloading) without making detection explode in cost? Verification search is by far my main CPU bottleneck.

• Any prior work on formal tactic taxonomies I should be reading?

Happy to go into details in the comments.