Interesting position for catching out cheaters :D

@Onyx_Chess said in #30:

Personally, my answer would be:

"In the name of the spirit of chess, Rxf7 seems like the kind of move that deserves to get some air time, regardless of if it's 100% fool proof and calculated all the way through to the check mate. It almost feels disrespectful, to chess, not to play it!"

I'm curious if Botvinnik saw the checkmate after he sacced his first rook on the 7th?

Very well expressed. Sometimes sacrifices are just crying to be played.
btw, thanks for posting the Botvinnik game. Very nice example.

getting back to the original, I would have invested a lot of time looking at Rxf7; depending on the time control, I probably would have played it on spec. If it were a longer time control and I couldn't find a way to make it work, I would have taken it as a personal defeat. If I fell back to playing Rc2, that would have been the psychological equivalent of resignation, because it represents a step backward. Once a first cautious retreat has been sounded, it becomes so much easier to signal the next, then the next, then comes the rout. You lose the thread of the position and its gone. Better to strike on promising but far from certain venture and know what you're trying to do than to try to play safely and not know what is going on.

fwiw, the clever R7c3 is an idea that would not have occurred to me on my own. Seeing it now, I can appreciate it; I love exchange sacrifices, and saccing an exchange to get rid of an opponent's best minor piece is something right up my alley. But this one is too subtle for me. That's a weakness, but I'm not sure what to call it. Weakness of vision, perhaps?

@Anon581 said in #27:

Actually, you can. This feature is already present on Lichess through the "Play with a friend" option. You choose the variant as "From Position", enter the position FEN and create a challenge: it redirects you to a window with a custom URL you can share with a friend, or even challenge another Lichess user by providing their username and they'll get a challenge notification for the game. (screenshot here: prnt.sc/nCNHZo95BDOG)

And before you ask, yes, the game can be a rated one as well.
Many thanks for letting me know! I wasn't aware that this was possible. Actually I only noticed it after setting up the custom position that it can allow a friend invitation.

Now, I'm not sure if it is fair to have such option to play rated games because obviously one player could quite deliberately setup an unfavourable custom game that is a disadvantage to their opponent to win easy ratings. If opponent isn't careful to analyze the board position and accepts such challenge, he/she will lose the game and rating points.

Unless a custom position was related to a particular chess opening like Italian, Fried Liver, Traxler, English Opening, Sicilian Defense, Queens Gambit, etc. Then I'll agree a rated game would be fair where there is an equal level playing position.

@GoLdEnFLAME said in #32:

Now, I'm not sure if it is fair to have such option to play rated games because obviously one player could quite deliberately setup an unfavourable custom game that is a disadvantage to their opponent to win easy ratings.

Of course lol, I do not suggest such positions where one side has a decisive advantage should be played rated. I was just saying that games with custom starting position FEN can be rated if the players want it to, custom starting position games need not necessarily be casual games.

And of course, any such rated game should either be an endgame or middlegame position that's roughly equal engine eval (say -0.5 to +0.5) with no huge material imbalance, or a known position right out of opening theory.

@the_puzzles said in #9:

In a real game I’d play R7c2 lol. All other moves are out of my calculation capabilities (:
yea, & yet someone may pretend he calculated Rxf7 all the way to the mate...
o boy, the wood is too deep & it's better to play safe moves xd

[Variant "From Position"]
[FEN "1r1qr1k1/2R2p1p/pb1p2pB/n3p3/8/1P3BP1/PQ2PP1P/2R3K1 w - - 0 1"]

1. Rxf7 Kxf7 2. Bd5+ Re6 (2... Kf6 3. Rc3) (2... Ke7 3. Bg5+) 3. Rc3 Qe7 (3... e4 4. Rf3+ exf3 5. Qg7+ Ke8 6. Bxe6) 4. Rf3+ Kg8 (4... Ke8 5. Bxe6) 5. b4

If you see mistake, correct me

Three different outcomes out of many. It looks easy but I would find it highly suspicious. Those non-linear combinations are difficult for humans IMHO.

https://lichess.org/j6PN0VGh/

In German we say „brettumfassend“ - full board comprehensive?

And this it is in what computers excel. Playing on both sides of the board safely like a sleepwalker.

Fun fact: place the Na5 on a7

Would you still go for it?

I think I would play Rxf7 even more in bullet or blitz. Sure the follow up isn't easy to calculate, but the same goes for my opponent too :)

It'll be hard to defend without much time. And even if I lose, it's fun who cares?

The rook is under attack, so it's quite natural to move the rook somewhere. Rxf7 is a bit crazy but there is nothing special in R7c3 or R7c2.