I have been experimenting with the Marshall as of late.
Most master games in the three main lines 11...c6, 11...Nf6, and 11...Bb7 seem to lead to a draw.
While this isn't necessarily a bad result with black, especially against a higher rated opponent, one has to wonder if there are any lines that offer better winning chances.
Are there any ideas that haven't been explored as often (maybe 11...Nb6, 11...Nf4, 11...Be6), or should I just stick to the Chigorin variations?
Most GM games in the Marshall end in draws since it's been analyzed to death, so GMs are booked up on theory for many many moves. It's basically like both players using an engine until say move 30, and then playing on their own. Playing out a dead equal position on move 30 is likely to end in a draw, since there's not as much character left in the game. A normal chess game starts on move 0 and is also objectively equal, but there are higher chances to make mistakes due to the increased complexity.
To be fair, there are some lines where White can play a risk-free game even at the expert/amateur level. E.g., some variations have well-known possibilities for an early forced draw. Or maybe White can get a middlegame/endgame position that only he has chances to win. But I don't think the Marshall falls into this category. Black has excellent compensation for the pawn, and he is the one attacking. Of course, he must attack in order to prove compensation for the pawn, but I digress.
If you're worried about your opponent being booked up on theory, you could play lines like the Chigorin or Zaitsev, as these tend to be more closed and strategical. But if your opponent knows a lot of theory, then chances are they'll know how to get a slight advantage in these lines. Nowadays in the Ruy Lopez, Black's best systems are the Berlin, Marshall, Open variation, and perhaps the Arkhangelsk. I'd recommend learning the Marshall and one other system on this list, making it more difficult for opponents to prepare for you. If that's not a big concern then just playing the Marshall alone is enough.
The best way to play is to come up with your own ideas. Anyone can memorize a single line which means a 900 can play like a GM as long as you stay in the lines they've memorized.
How do you come up with unique lines?
First, I like getting the general idea of an opening and then playing it in blitz. Ive come up with good lines doing that. Just play what you would normally play and sometimes you stumble into great moves.
Also, looking at win% and engine evaluation can help you find lines that are overlooked. For example, my main line in the Evans gambit is a move I found from Stockfish but has never been played in a tournament. SF considers it the best move and gives white a small edge.
You can also sort lichess' database by rating. Look for trappy lines that are common. My main d4 defense came out of me discovering a trappy line that's the most common line vs <2000 players. I've built an entire system out of that that's a super solid line but can transpose to very aggressive lines. Also, ridiculously easy to learn.
And, looking at old lines and rehabilitating them. An example might be Damiano's defense. Most people assume white is winning easily but its actually playable as black if you know the lines. Silman had an article on his website back in the day.
