I agree with you. I can see it referring to a chess move, chess had been referenced previously.
Trident missile is more of a stretch but missiles had been referenced.
I don’t recall an avalanche ever being referenced.
Meaning as yet unknown also works for me.
I would like it if D5 were referring to a chess move; but, I am a decent player and still cannot fathom the “Secret” meaning of the Marshall-Capablanca game as it relates to our current situation (even after watching a play-through, with commentary, of the entire game).
Somehow, I don’t think Q is going to communicate using a chess analogy so deep that only chess masters who are also close followers of Trump/Q/Spygate can even fathom it.
After all, the purpose of Q is to COMMUNICATE clues whereby we can build an accurate overall picture without anyone breaking the law concerning classified information or (legally protected) privacy of individuals, even perps.
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CODA:
1) IF there is a message in the game, it was in Marshall’s brazen attack, sacrificing a pawn early to get all his pieces flying at Capa’s King.
2) However, the attack ultimately failed. After securing the safety of his King, Capablanca devastated Marshall’s position.
If you’ll note in one of the most recent Q drops, Q uses D5 and snowball in the same paragraph. D5 IS avalanche.