9. ... f5 in the old/modern CK ain’t stupid

@Sarg0n

i'm not CK player at all. i played it a few months when starting chess and that's it....
I must say i'm impressed by the move f5. i don't think i would ever come with such a move.
from all the moves mentionned that's the one i'd go for. It certainly does offer nice counterplay.

when speaking about g6 and h6 you say they're outdated. do you mean bad? or at least inferior?

no matter the objective value of h5 i don't think i'd ever play that. It looks really weakening. is the idea h4 after 0-0?

#10
"A pawn is a pawn" - Fischer

I hope you‘ll remember when you play the King‘s Gambit^^, #12.

Schandorff mentions the sideline, interesting surprise.

If white declines the pawn Black doesn’t care about it. Just Nd7!

#15
"A sacrifice is best refuted by accepting it" - Steinitz
I still think however, that the white battery Bd3 Qc2 is useless. More logical seems Bc4, O-O with the idea of trading heavy pieces along the e-file and enter an endgame to queen pawn d4.

Schandorff: „It was not until a few years ago that people started realizing it might be a cool idea.“

Nevertheless he considers it a surprise weapon at faster time limits (which is the new normal IMHO) and calls the 9. ... h5! the modern, dynamic solution.

Interesting that I had exactly felt the same before opening the book.

Blessed are those who have got both books. I ordered Rambaldi and got Schandorff...

However, I did some testing and research on my own using ChessBase and Stockfish. And playing training games for a couple of weeks.