Quick Ruy Lopez question

Also, while I am at it, does anyone know any deep theory of the Marshall Attack? I know this is an extra question, but I would like to know.

i thin then

Bg3-h3

and bishop sacrifice could happen to attack with queen ,other bishop and knight.

for white,a hard situation.

I think black usually refrains from playing 8...Bg4 because it doesn't put any pressure on white if he hasn't played his pawn to d4.

So usually, white will go on playing 9.d3 then his usual kingside attack plan with Nbd2-Nf1-h3-g4-Ng3 etc. winning a tempo on the bishop in the process.

Here is a game that illustrates these ideas.

As for Marshall theory, it's really huge, maybe you could search for articles on Marshall Gambit with the search bar.

Basically, black gets an attack + board control for one pawn.

If 8.c3 Bg4, 9.d3 with the idea of Nbd2, Nf1, h3 and if Bh5, then Ng3 and if Bg6, possibly Nh4 and Nhf5. If 8.c3 0-0 9.d4, then Bg4 puts pressure on d4 by pinning the knight. White then has 10.d5 or h3 or Be3 or a4.

Thanks. One last question for anyone who wants to answer: what is your favorite anti-marshall and why?

I tried once 9. h3, but all I got is just equalized and drew.

Playing in the Marshall tournament gave me an idea that if you confidently play Marshall, you should try to play it with White too, especially modern main line: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Be7 6.Re1 b5 7.Bb3 0-0 8.c3 d5 9.exd5 Nxd5 10.Nxe5 Nxe5 11.Rxe5 c6 12.d4 Bd6 13.Re1 Qh4 14.g3 Qh3 15.Re4 (often sacrificing the exchange on this square).

I have once played Bg4 where you specified. I ended up behind in development and, while I was frantically trying to castle, my opponent got an advantage. The main problem for Black is that, even with the knight pinned, White still has enough defenders play 9d4 especially considering Black cannot exchange without long-term central and kingside pressure. Hope this helps.

My favorite anti-Marshall line is 5 d4 !