Kerangali wrote on 08/22/23 at 11:42:33:

Thanks for pointing out that course. I was not aware of it. As to your question, one advantage of playing 4...Nf6 instead of 4...d6 is to avoid the line:  1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. Bc6 bc6 6d4. This can be answered by 6...exd or 6...f6. With preparation, I think Black can welcome this line.

It seems that Jones' course tries to provide a ...g6 response whenever possible in the double-king pawn opening. It's an interesting idea and I wonder how well he can pull it off!

I prefer PGN or CBV files, but I have delved into the Chessable world. I often play through the moves in Chess Opening Wizard. It's a bit tedious. On the other hand, Chessable expects the user to play through moves anyway.

I realize that I was a little terse in my prior comment, so I will now expand now. My reasoning was that
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. c3 f5!? 6. exf5 Bf5
and
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. O-O Bg4 6. h3 h5!?
make a good match. They lead to disruptive chess, denying White a simple advantage. 

Other approaches by Black, for example a king side fianchetto, can be attempted against either 5c3 or 5O-O, so why not do so against both moves?

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. O-O Bg4 6. h3 h5!? Here7.d4 is the main move, but it is very complicated. White might try for something simpler with 7. Bc6 bc6 8. d4 (...Qf6) Bf3 9. Qf3 ed4.



Now White can consider 10e5, 10Re1, 10c3 and 10Rd1. Black is a pawn up for the moment but lags in development. His queen side pawns may become vulnerable. He might get something going on the king side with g5-4.

There are several resources available:  analysis at ChessPublishing and elsewhere, games played, and computer evaluations. The computer gives White the advantage for the moment. I analyzed one line with the computer and at some point it recalibrated and gave Black equality. To paraphrase a song by Billy Joel, it never is wrong, it just changes its mind. For now at least, I'll go with human evaluations!

So an ancient main line move gets "!!" ... ah, marketing.

Kerangali wrote on 07/20/23 at 09:06:13:

There's a mention of freezing White's queenside with ...Bd3, which I figured must be a reference to the Siesta (with 7. 0-0).

This screenshot apparently showing Black's ...Qg4-g3 must be an extreme case of threat stronger than execution

I just happened upon another source. (Sale ends soon).

Club Player's Repertoire for Black with 1...e5 by GM Krisztian Szabo (10 hours and 22 mins Running Time) 

https://www.modern-chess.com/club-players-repertoire-for-black-with-1-e5-by-gm-k...

Chapter 1. Kings Gambit 3.Bc4
Chapter 2. Kings Gambit 3.Nf3 Nf6
Chapter 3. Vienna Game (Part I)
Chapter 4. Vienna Game (Part II)
Chapter 5. Vienna Game (Part III)
Chapter 6. Centre Game
Chapter 7. Goering Gambit
Chapter 8. Ponziani Opening
Chapter 9. Four Knights 4.g3
Chapter 10. Four Knights 4.d4
Chapter 11. Four Knights 4.Bb5
Chapter 12. Scotch Gambit
Chapter 13. Scotch Game Secondary Lines
Chapter 14. Scotch Game Main Line
Chapter 15. Italian Game 4.Ng5
Chapter 16. Italian Game 4.d3
Chapter 17. Ruy Lopez Exchange 5.Nc3
Chapter 18. Ruy Lopez Exchange 5.0-0
Chapter 19. Ruy Lopez Deferred Steinitz (Part I)
Chapter 20. Ruy Lopez Deferred Steinitz (Part II)

The Papaioannou link is here (preview at the bottom): 
https://www.modern-chess.com/1-e4-e5-for-black-repertoire-against-the-ruy-lopez-...

Michael Ayton wrote on 07/03/23 at 07:37:00:


I found the NIC Surveys:  NIC YBK 119, 126, and 128. What I found from Roiz at Modern-chess was the Breyer and White sidelines.

The ChessPublishing archives have a lot of material.