[vunderba]

Ah yeah that'll get complicated quickly. :( It'd be nice if stockfish or its variants exposed the "ply searcher" with some kind of a callback so you could quickly kill a ply based on your custom constraints.

When I was doing some research into rolling my own chess engine about 5 years ago I stumbled across this:

https://github.com/josefjadrny/js-chess-engine

But you'd have to modify its minimax search and now we're getting pretty deep down the rabbit hole. Either way, good luck!